From Reuters Health Information
By C. Vidya Shankar
NEW YORK (Reuters Health) Sep 04 - BCG vaccine administered at 10 weeks of age produces a better immune response against Mycobacterium tuberculosis than when given at birth, according to the results of a small study from South Africa, published in the September issue of Vaccine.
The protective effect of BCG against tuberculosis varies depending on such issues as the vaccine strain, the route of administration, dose and host immune response, Dr. Willem Hanekom and colleagues explain. As the cell-mediated immune response is "immature" at birth, delaying the vaccine could enhance the immune response, they propose.
To test their hypothesis, Dr. Hanekom, from the University of Capetown, and his team conducted a randomized trial in which 25 neonates received BCG vaccine by intradermal injection at birth, whereas 21 received it at ten weeks of age. Infants in both groups were born healthy at term to HIV-negative mothers, and had no contact with tuberculosis.
The immune response to BCG was assessed 10 weeks and 1 year after vaccination by assay of the cytokines interferon gamma, tumor necrosis factor-alpha, and Interleukin-2, all produced by T helper 1 CD4 T cells.
Cytokine production by BCG-specific CD4 T cells were significantly greater among the delayed vaccine group both at 10 weeks and 1 year after vaccination, they observed. The response was most significant one year after vaccination, they note.
"Delayed vaccination resulted in an enhanced memory CD4 T cell response at 1 year of age," Dr. Hanekom observed. This results in improved long-term immunity, "particularly of the kind regarded as important for protection against TB," he explained.
The researcher noted that delayed BCG vaccine resulted in an increased production of "polyfunctional" BCG-specific CD4 T cells. "Polyfunctional cells make multiple cytokines together -- we think these cells are important for protection against TB," he said.
If these findings are confirmed by larger studies, they "could have wide-ranging implications for BCG vaccination practices, world-wide," Dr. Hanekom concluded.
Vaccine 2009;27:5488-5495.
Thursday, September 10, 2009
Fits & Fever
From Medscape Medical News
Antipyretic Agents May Not Prevent Febrile Seizures
Laurie Barclay, MD
September 9, 2009 — Antipyretic agents may not prevent febrile seizures, according to the results of a randomized, placebo-controlled, double-blind trial reported in the September issue of the Archives of Pediatrics & Adolescent Medicine.
"The general assumption has been that fever is the key factor in the initiation of a febrile seizure, and it has, therefore, been supposed that the administration of antipyretic agents during febrile episodes will prevent seizures and their recurrences by the lowering of the fever," write Teemu Strengell, MD, from the University of Oulu in Oulu, Finland, and colleagues.
"This has not proved to be the case in clinical trials, however."
The goal of this study was to assess the effectiveness of different antipyretic agents and their highest recommended doses for preventing febrile seizures. At 5 hospitals, each of which was the only pediatric hospital in its region, 231 children who had their first febrile seizure between January 1, 1997, and December 31, 2003, were enrolled and observed for 2 years.
During follow-up, all febrile episodes were treated first with either rectal diclofenac or placebo, and after 8 hours, treatment was continued with oral ibuprofen, acetaminophen, or placebo. The primary endpoint of the study was recurrence of febrile seizures.
Of 851 febrile episodes occurring during follow-up, 89 were associated with a febrile seizure. Of the 231 children enrolled, 54 (23.4%) had recurrent febrile seizures. The treatment groups did not differ significantly in the main measure of effect, and the effect estimates were similar. The rate of febrile seizure recurrence was 23.4% (46/197) in those receiving antipyretic agents and 23.5% (8/34) in those receiving placebo (difference, 0.2; 95% confidence interval [CI], −12.8 to 17.6; P = .99).
Independent of the medication given, fever was significantly higher during the episodes with seizure vs those without seizure (39.7°C vs 38.9°C; difference, 0.7°C; 95% CI, −0.9°C to −0.6°C; P < .001).
"Antipyretic agents are ineffective for the prevention of recurrences of febrile seizures and for the lowering of body temperature in patients with a febrile episode that leads to a recurrent febrile seizure," the study authors write.
Limitations of this study include inability to exclude the possibility of a lesser effect that could be detected with a greater sample size. Parents were permitted to give their child an extra dose of open-label acetaminophen for temperature greater than 40.0°C, which could cause some dilutional bias.
"Because antipyretic agents are effective during a febrile episode that does not lead to a seizure, their use should not differ between patients with and without previous febrile seizures," the study authors conclude. "Parents should be informed about the inefficacy of antipyretic agents during a febrile episode that leads to a febrile seizure and about the benign nature of febrile seizures themselves."
Special State Grants for Health Research in the Department of Pediatrics and Adolescence in the Oulu University Hospital supported this study. The study authors have disclosed no relevant financial relationships.
Arch Pediatr Adolesc Med. 2009;163:799-804.
Antipyretic Agents May Not Prevent Febrile Seizures
Laurie Barclay, MD
September 9, 2009 — Antipyretic agents may not prevent febrile seizures, according to the results of a randomized, placebo-controlled, double-blind trial reported in the September issue of the Archives of Pediatrics & Adolescent Medicine.
"The general assumption has been that fever is the key factor in the initiation of a febrile seizure, and it has, therefore, been supposed that the administration of antipyretic agents during febrile episodes will prevent seizures and their recurrences by the lowering of the fever," write Teemu Strengell, MD, from the University of Oulu in Oulu, Finland, and colleagues.
"This has not proved to be the case in clinical trials, however."
The goal of this study was to assess the effectiveness of different antipyretic agents and their highest recommended doses for preventing febrile seizures. At 5 hospitals, each of which was the only pediatric hospital in its region, 231 children who had their first febrile seizure between January 1, 1997, and December 31, 2003, were enrolled and observed for 2 years.
During follow-up, all febrile episodes were treated first with either rectal diclofenac or placebo, and after 8 hours, treatment was continued with oral ibuprofen, acetaminophen, or placebo. The primary endpoint of the study was recurrence of febrile seizures.
Of 851 febrile episodes occurring during follow-up, 89 were associated with a febrile seizure. Of the 231 children enrolled, 54 (23.4%) had recurrent febrile seizures. The treatment groups did not differ significantly in the main measure of effect, and the effect estimates were similar. The rate of febrile seizure recurrence was 23.4% (46/197) in those receiving antipyretic agents and 23.5% (8/34) in those receiving placebo (difference, 0.2; 95% confidence interval [CI], −12.8 to 17.6; P = .99).
Independent of the medication given, fever was significantly higher during the episodes with seizure vs those without seizure (39.7°C vs 38.9°C; difference, 0.7°C; 95% CI, −0.9°C to −0.6°C; P < .001).
"Antipyretic agents are ineffective for the prevention of recurrences of febrile seizures and for the lowering of body temperature in patients with a febrile episode that leads to a recurrent febrile seizure," the study authors write.
Limitations of this study include inability to exclude the possibility of a lesser effect that could be detected with a greater sample size. Parents were permitted to give their child an extra dose of open-label acetaminophen for temperature greater than 40.0°C, which could cause some dilutional bias.
"Because antipyretic agents are effective during a febrile episode that does not lead to a seizure, their use should not differ between patients with and without previous febrile seizures," the study authors conclude. "Parents should be informed about the inefficacy of antipyretic agents during a febrile episode that leads to a febrile seizure and about the benign nature of febrile seizures themselves."
Special State Grants for Health Research in the Department of Pediatrics and Adolescence in the Oulu University Hospital supported this study. The study authors have disclosed no relevant financial relationships.
Arch Pediatr Adolesc Med. 2009;163:799-804.
Wednesday, September 9, 2009
Eggs & Cholesterol?
Current Recommendations
The American Heart Association[31,32] Diet and Lifestyle Recommendations for Cardiovascular Disease Risk Reduction are listed in Table 1. The current recommendations reflect a shift toward looking at dietary patterns and overall diet quality rather than focusing on specific nutrients and a diet based more on inclusion of a wide range of foods and less on avoidance of particular foods or ingredients. Whereas there was previously a stated recommendation to limit eggs to 4 yolks per week, this food-specific recommendation is not in the current guidelines. The American Heart Association recommendation is to limit dietary cholesterol to <300 mg/d. The average egg yolk contains on average 213 mg of cholesterol.
If eggs are judged on their nutritional content, convenience, and cost, the positive contributions of eggs may outweigh the potential risk associated with the cholesterol. This may be particularly true for healthy elderly individuals whose cholesterol risk and nutritional needs differ from earlier years. For individuals with diabetes or major risk factors for CHD, the recommendation to limit dietary cholesterol to <200 mg/d[33] allows for less frequent use of unmodified egg products. Along with the numerous modified egg products on the market today (eg, Egg Beaters), there will likely be additional egg and egg products with higher lutein and lower cholesterol in the future.[34,35]
Table 1. American Heart Association 2006 Diet and Lifestyle Recommendations for Cardiovascular Disease Risk Reduction[32]
Balance calorie intake and physical activity to achieve or maintain a healthy body weight
Consume a diet rich in vegetables and fruit
Choose whole-grain, high-fiber foods
Consume fish, especially fatty fish, at least twice per week
Limit your intake of saturated fat to <7% of energy, trans fat to <1% of energy, and cholesterol to <300 mg/d by
Choosing lean meats and vegetable alternatives
Selecting fat-free (skim), 1% fat, and low-fat dairy products
Minimizing the intake of partially hydrogenated fats
Minimize the intake of beverages and foods with added sugars
Choose and prepare foods with little or no salt
If you consume alcohol, do so in moderation
When you eat food prepared outside of the home, follow American Heart Association diet and lifestyle recommendations
for whole article see blog http://drtanpohtin.blogspot.com
The American Heart Association[31,32] Diet and Lifestyle Recommendations for Cardiovascular Disease Risk Reduction are listed in Table 1. The current recommendations reflect a shift toward looking at dietary patterns and overall diet quality rather than focusing on specific nutrients and a diet based more on inclusion of a wide range of foods and less on avoidance of particular foods or ingredients. Whereas there was previously a stated recommendation to limit eggs to 4 yolks per week, this food-specific recommendation is not in the current guidelines. The American Heart Association recommendation is to limit dietary cholesterol to <300 mg/d. The average egg yolk contains on average 213 mg of cholesterol.
If eggs are judged on their nutritional content, convenience, and cost, the positive contributions of eggs may outweigh the potential risk associated with the cholesterol. This may be particularly true for healthy elderly individuals whose cholesterol risk and nutritional needs differ from earlier years. For individuals with diabetes or major risk factors for CHD, the recommendation to limit dietary cholesterol to <200 mg/d[33] allows for less frequent use of unmodified egg products. Along with the numerous modified egg products on the market today (eg, Egg Beaters), there will likely be additional egg and egg products with higher lutein and lower cholesterol in the future.[34,35]
Table 1. American Heart Association 2006 Diet and Lifestyle Recommendations for Cardiovascular Disease Risk Reduction[32]
Balance calorie intake and physical activity to achieve or maintain a healthy body weight
Consume a diet rich in vegetables and fruit
Choose whole-grain, high-fiber foods
Consume fish, especially fatty fish, at least twice per week
Limit your intake of saturated fat to <7% of energy, trans fat to <1% of energy, and cholesterol to <300 mg/d by
Choosing lean meats and vegetable alternatives
Selecting fat-free (skim), 1% fat, and low-fat dairy products
Minimizing the intake of partially hydrogenated fats
Minimize the intake of beverages and foods with added sugars
Choose and prepare foods with little or no salt
If you consume alcohol, do so in moderation
When you eat food prepared outside of the home, follow American Heart Association diet and lifestyle recommendations
for whole article see blog http://drtanpohtin.blogspot.com
Saturday, September 5, 2009
Report New Cases of Guillain-Barré After H1N1 Flu Vaccine
From Medscape Medical News
Allison Gandey
September 1, 2009 — Neurologists should be vigilant in tracking any new cases of Guillain-Barré syndrome after patients have received the H1N1 flu vaccine, say officials. The American Academy of Neurology (AAN) is teaming up with the Centers for Disease Control and Prevention (CDC) to make sure doctors remain alert.
Guillain-Barré has been linked to several vaccines, including the preparation for the 1976 swine flu. In a statement issued by the AAN, experts said that although they do not expect the 2009 H1N1 vaccine to increase the risk for the autoimmune disease, this is a concern with any pandemic vaccine. "The active participation of neurologists is going to be critical for monitoring for any possible increase in Guillain-Barré following 2009 H1N1 influenza vaccination," AAN spokesperson Orly Avitzur, MD, said in a news release.
The H1N1 vaccine is currently in production. High-risk groups will be encouraged to receive the vaccine this fall. Infants, children, young adults, pregnant women, adults 25 years and older with underlying health conditions, and healthcare workers are considered good candidates for the vaccine.
Doctors are being asked to report adverse events using the standard CDC and US Food and Drug Administration Vaccine Adverse Event Reporting System.
Guillain-Barré affects 1 to 4 people per 100,000 annually around the world. It causes respiratory failure requiring ventilation in an estimated 25% of people, and between 4% and 15% die.
The AAN guidelines on the treatment of Guillain-Barré are available online.
Allison Gandey
September 1, 2009 — Neurologists should be vigilant in tracking any new cases of Guillain-Barré syndrome after patients have received the H1N1 flu vaccine, say officials. The American Academy of Neurology (AAN) is teaming up with the Centers for Disease Control and Prevention (CDC) to make sure doctors remain alert.
Guillain-Barré has been linked to several vaccines, including the preparation for the 1976 swine flu. In a statement issued by the AAN, experts said that although they do not expect the 2009 H1N1 vaccine to increase the risk for the autoimmune disease, this is a concern with any pandemic vaccine. "The active participation of neurologists is going to be critical for monitoring for any possible increase in Guillain-Barré following 2009 H1N1 influenza vaccination," AAN spokesperson Orly Avitzur, MD, said in a news release.
The H1N1 vaccine is currently in production. High-risk groups will be encouraged to receive the vaccine this fall. Infants, children, young adults, pregnant women, adults 25 years and older with underlying health conditions, and healthcare workers are considered good candidates for the vaccine.
Doctors are being asked to report adverse events using the standard CDC and US Food and Drug Administration Vaccine Adverse Event Reporting System.
Guillain-Barré affects 1 to 4 people per 100,000 annually around the world. It causes respiratory failure requiring ventilation in an estimated 25% of people, and between 4% and 15% die.
The AAN guidelines on the treatment of Guillain-Barré are available online.
Friday, September 4, 2009
First H1N1 Flu Vaccine Trials Underway
From Medscape Medical News
Emma Hitt
August 21, 2009 — No safety concerns have been reported with the H1N1 influenza vaccine so far in a clinical trial of adults and the elderly, and the planned trials are accruing well.
Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, National Institutes of Health, spoke today at a US Centers for Disease Control and Prevention media briefing.
Five major trials are underway to evaluate H1N1 vaccines made by 2 manufacturers, Sanofi Pasteur and CSL Biotherapies. Two trials will compare 15 vs 30 μg and 1 vs 2 doses of each of the vaccines in healthy adults aged 18 years and older.
A comparable study is now underway in children aged 6 months to 17 years. A fourth and fifth trial will evaluate simultaneous vs sequential administration of the seasonal flu vaccine and the Sanofi Pasteur H1N1 vaccine in healthy adults and children, respectively.
First-dose data from the trial in adults are expected in mid-September, Dr. Fauci said. "If all goes well, second-dose data will be available somewhere around mid-October," he added. According to Dr. Fauci, the apparent safety of the vaccine in the trial of adults triggered the initiation of the pediatric trial on August 19 and 20.
Trials scheduled to begin in early September will evaluate 3 vaccine products in pregnant women, using 1 vs 2 doses and 15 vs 30 μg, with approximately 120 pregnant women in each trial.
Trials are also being planned for the use of adjuvants in "what we call a mix and match, where we take the antigen from one company and use the adjuvant from another company," Dr. Fauci said. "Those studies are scheduled to start somewhere in mid- to late September." Overall, about 4500 individuals will be studied in the clinical trials of the vaccines.
Jay Butler, MD, director, H1N1 Vaccine Task Force, Centers for Disease Control and Prevention, provided an update of US H1N1 statistics, as well as a report on activity in the Southern hemisphere and the status of vaccine production.
To date, there have been 7963 hospitalizations and 522 deaths that have been laboratory confirmed as being caused by novel H1N1 virus. "It's important to keep in mind that these numbers radically underestimate the number of cases that actually occur," he noted.
Seasonal flu activity has all but stopped, and nearly all cases now observed are H1N1. "Two states, Alaska and Maine, are reporting widespread influenza activity at this time," he said.
According to Dr. Butler, activity in the Southern hemisphere appears to be decreasing. In addition, the epidemiology of the disease caused by the virus in the Southern hemisphere is "very similar to that described in the United States this past spring," he said.
"There have been no significant changes detected in the influenza virus isolated from persons in the southern hemisphere as compared to viruses isolated from persons in the northern hemisphere," said Dr. Butler.
Five manufacturers are contracted to make the vaccine. Availability of between 45 million and 52 million doses of vaccine is expected by mid-October, and "this will be followed by weekly availability of vaccine up to about 195 million doses by the end of the year." However, Dr. Butler pointed out that many unforeseen variables can influence the production process.
Disclosure: Emma Hitt, PhD, has disclosed no relevant financial relationships.
Emma Hitt
August 21, 2009 — No safety concerns have been reported with the H1N1 influenza vaccine so far in a clinical trial of adults and the elderly, and the planned trials are accruing well.
Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, National Institutes of Health, spoke today at a US Centers for Disease Control and Prevention media briefing.
Five major trials are underway to evaluate H1N1 vaccines made by 2 manufacturers, Sanofi Pasteur and CSL Biotherapies. Two trials will compare 15 vs 30 μg and 1 vs 2 doses of each of the vaccines in healthy adults aged 18 years and older.
A comparable study is now underway in children aged 6 months to 17 years. A fourth and fifth trial will evaluate simultaneous vs sequential administration of the seasonal flu vaccine and the Sanofi Pasteur H1N1 vaccine in healthy adults and children, respectively.
First-dose data from the trial in adults are expected in mid-September, Dr. Fauci said. "If all goes well, second-dose data will be available somewhere around mid-October," he added. According to Dr. Fauci, the apparent safety of the vaccine in the trial of adults triggered the initiation of the pediatric trial on August 19 and 20.
Trials scheduled to begin in early September will evaluate 3 vaccine products in pregnant women, using 1 vs 2 doses and 15 vs 30 μg, with approximately 120 pregnant women in each trial.
Trials are also being planned for the use of adjuvants in "what we call a mix and match, where we take the antigen from one company and use the adjuvant from another company," Dr. Fauci said. "Those studies are scheduled to start somewhere in mid- to late September." Overall, about 4500 individuals will be studied in the clinical trials of the vaccines.
Jay Butler, MD, director, H1N1 Vaccine Task Force, Centers for Disease Control and Prevention, provided an update of US H1N1 statistics, as well as a report on activity in the Southern hemisphere and the status of vaccine production.
To date, there have been 7963 hospitalizations and 522 deaths that have been laboratory confirmed as being caused by novel H1N1 virus. "It's important to keep in mind that these numbers radically underestimate the number of cases that actually occur," he noted.
Seasonal flu activity has all but stopped, and nearly all cases now observed are H1N1. "Two states, Alaska and Maine, are reporting widespread influenza activity at this time," he said.
According to Dr. Butler, activity in the Southern hemisphere appears to be decreasing. In addition, the epidemiology of the disease caused by the virus in the Southern hemisphere is "very similar to that described in the United States this past spring," he said.
"There have been no significant changes detected in the influenza virus isolated from persons in the southern hemisphere as compared to viruses isolated from persons in the northern hemisphere," said Dr. Butler.
Five manufacturers are contracted to make the vaccine. Availability of between 45 million and 52 million doses of vaccine is expected by mid-October, and "this will be followed by weekly availability of vaccine up to about 195 million doses by the end of the year." However, Dr. Butler pointed out that many unforeseen variables can influence the production process.
Disclosure: Emma Hitt, PhD, has disclosed no relevant financial relationships.
Thursday, September 3, 2009
FDA Safety Labeling Changes : Gardasil
From Medscape Medical News >
FDA Safety Changes: Actonel, Gardasil, Myfortic
Yael Waknine
September 2, 2009 — The US Food and Drug Administration (FDA) has approved safety labeling revisions to warn of the potential for osteonecrosis of the jaw in patients receiving risedronate sodium and other bisphosphonates, the potential for syncope after administration of a human papillomavirus vaccine, and the risk for pure red cell aplasia in patients receiving immunosuppressive treatment with mycophenolic acid delayed-release tablets.
HPV Vaccine (Gardasil) May Be Linked to Postinjection Fainting Episodes
The FDA approved in July safety labeling revisions for human papillomavirus (HPV) quadrivalent recombinant vaccine (Gardasil; Merck and Co, Inc) to warn of the potential for syncope.
Syncope, sometimes associated with tonic-clonic and other seizure-like activity, has been reported after administration of the HPV vaccine. Because fainting can result in falling and injury, patients should be observed for a 15-minute period after receiving the vaccine and encouraged to remain seated or lying down for this length of time.
The FDA notes that when syncope is associated with tonic-clonic movements, the activity is usually transient and typically passes when patients adopt a supine or Trendelenburg position.
The quadrivalent vaccine is indicated for use in girls and young women aged 9 through 26 years for the prevention of cervical, vulvar, and vaginal cancer caused by HPV types 16 and 18; genital warts caused by HPV types 6 and 11; and certain dysplastic lesions caused by HPV types 6, 11, 16, and 18.
Gardasil Prescribing Information
FDA Safety Changes: Actonel, Gardasil, Myfortic
Yael Waknine
September 2, 2009 — The US Food and Drug Administration (FDA) has approved safety labeling revisions to warn of the potential for osteonecrosis of the jaw in patients receiving risedronate sodium and other bisphosphonates, the potential for syncope after administration of a human papillomavirus vaccine, and the risk for pure red cell aplasia in patients receiving immunosuppressive treatment with mycophenolic acid delayed-release tablets.
HPV Vaccine (Gardasil) May Be Linked to Postinjection Fainting Episodes
The FDA approved in July safety labeling revisions for human papillomavirus (HPV) quadrivalent recombinant vaccine (Gardasil; Merck and Co, Inc) to warn of the potential for syncope.
Syncope, sometimes associated with tonic-clonic and other seizure-like activity, has been reported after administration of the HPV vaccine. Because fainting can result in falling and injury, patients should be observed for a 15-minute period after receiving the vaccine and encouraged to remain seated or lying down for this length of time.
The FDA notes that when syncope is associated with tonic-clonic movements, the activity is usually transient and typically passes when patients adopt a supine or Trendelenburg position.
The quadrivalent vaccine is indicated for use in girls and young women aged 9 through 26 years for the prevention of cervical, vulvar, and vaginal cancer caused by HPV types 16 and 18; genital warts caused by HPV types 6 and 11; and certain dysplastic lesions caused by HPV types 6, 11, 16, and 18.
Gardasil Prescribing Information
Sunday, August 30, 2009
Update: Novel Influenza A (H1N1) Virus Infections --- Worldwide, May 6, 2009
From Morbidity & Mortality Weekly Report
Published: 08/14/2009
Since mid-April 2009, CDC, state and local health authorities in the United States, the World Health Organization (WHO), and health ministries in several countries have been responding to an outbreak of influenza caused by a novel influenza A (H1N1) virus.[1] In March and early April 2009, Mexico experienced outbreaks of respiratory illness subsequently confirmed by CDC and Canada to be caused by the novel virus. The influenza strain identified in U.S. patients was genetically similar to viruses isolated from patients in Mexico.[2] Since recognition of the novel influenza A (H1N1) virus in Mexico and the United States, as of May 6, a total of 21 additional countries had reported cases, with a total of 1,882 confirmed cases worldwide. Several WHO member states are conducting ongoing investigations of this worldwide outbreak, and WHO is monitoring and compiling surveillance data and case reports. On April 29, WHO raised the level of pandemic alert from phase 4 to phase 5, indicating that human-to-human spread of the virus had occurred in at least two countries in one WHO region. This report provides an update of the initial investigations and spread of novel influenza A (H1N1) virus worldwide.
Mexico
Since implementing enhanced surveillance on April 17, the number of suspected cases has increased rapidly, along with hospitalizations for severe acute respiratory illness (Figure 1). As of May 5, using an updated case definition of fever plus cough or sore throat for a suspected case and real-time reverse transcription–polymerase chain reaction (rRT-PCR) or viral culture for a laboratory-confirmed case, Mexico had identified 11,932 suspected cases and 949* cases of laboratory-confirmed novel influenza A (H1N1) virus infection, including 42 patients who died. Cases with laboratory-confirmed infection have been identified in 27 of 31 Mexican states and the Federal District. Confirmed cases in Mexico and in the United States have a similar age distribution (Table). Information is available on the clinical course of illness for 22 patients with laboratory-confirmed illness who were hospitalized, including seven patients who died. Five of the 15 surviving patients and one of the seven patients who died had underlying chronic medical conditions. Additional details on the clinical signs and symptoms of these and other patients are being collected. Among patients with confirmed cases for whom information was available, 56 (98%) of 57 reported fever, 49 (94%) of 52 reported cough, 23 (79%) of 29 reported dyspnea, 35 (80%) of 44 reported headache, and 34 of (83%) 41 reported rhinorrhea. The government of Mexico has instituted several measures to slow disease transmission and reduce mortality, including closure of all schools and avoidance of large public gatherings, distribution of oseltamivir to all health-care units, publication of specific clinical guidelines, and establishment of a call center to educate members of the public who are seeking health-care information.
United States
After recognition of the first cases of infection with the novel influenza A (H1N1) virus, CDC and state health departments initiated enhanced surveillance measures to identify additional cases. As of May 6, a total of 1,487 confirmed† and probable cases had been reported from 43 states, including 642 confirmed cases (reported from 41 states) and 845 probable cases (reported from 42 states). Current experience with laboratory testing results indicates that the probability of laboratory confirmation for probable cases is > 99%. States with the most confirmed cases are Illinois (122 cases), New York (97), California (67), Texas (61), and Arizona (48). Dates of illness onset for patients with confirmed or probable illness range from March 28 to May 4 (Figure 2), although the most recent case counts do not account for testing and reporting delays. Among persons with laboratory-confirmed illness, 35 hospitalized patients have been reported from 16 states, including two patients from Texas who died, both with underlying medical conditions. The age distribution of persons with laboratory-confirmed disease ranged from 3 months to 81 years (Table). A total of 18 patients were aged < 2 years, and 31 were aged 2–4 years.
The age distribution of the 35 laboratory-confirmed hospitalized patients ranged from 6 months to 53 years (median: 15 years). Among patients with confirmed disease for whom data were available, 262 (90%) of 292 reported fever, 249 (84%) of 296 reported cough, 176 (61%) of 290 reported sore throat, 65 (26%) of 249 reported diarrhea, and 54 (24%) of 221 reported vomiting.
Other Countries
On April 26, the first cases of novel influenza A (H1N1) virus infection outside of the United States and Mexico were reported in Canada. As of May 6, WHO had reported that 309 persons with laboratory-confirmed disease had been identified in 21 countries other than Mexico and the United States. Confirmed cases have been reported from Asia (Hong Kong S.A.R. and Korea), the Pacific region (New Zealand), the Middle East (Israel), Europe, and Central and South America (El Salvador, Costa Rica, Colombia, and Guatemala) (Figure 3).
Of 178 patients for whom travel history was available, 145 (82%) reported recent travel to Mexico, and four (2%) reported travel to the United States. Among those who had not traveled to Mexico, 17 (52%) reported contact with a returning traveler from Mexico. Canada, Germany, Spain, and the United Kingdom all have reported evidence of in-country, second-generation, human-to-human transmission (e.g., a health-care worker in Germany who had cared for a patient with a confirmed infection). No reports have been made of sustained, community-wide transmission in affected countries. Consistent with cases in North America, most of the cases reported from other countries have been among young adults, with a median age of 27.1 years (range: 2–62 years, N = 45). The majority of cases in other countries have been uncomplicated, and no deaths have been reported; four patients have been hospitalized.§
Editorial Note
Early surveillance data from this outbreak suggest that the novel influenza A (H1N1) virus has the potential for efficient, rapid spread among countries. Although the illness associated with infection generally seems self-limited and uncomplicated, a substantial number of cases of severe disease and death has been reported in previously healthy young adults and children. Several characteristics of this outbreak appear unusual compared with a typical influenza seasonal outbreak. First, the percentage of patients requiring hospitalization appears to be higher than would be expected during a typical influenza season.[3] Second, the age distribution of hospitalizations for novel influenza A (H1N1) virus infection is different than that of hospitalizations for seasonal influenza, which typically occur among children aged < 2 years, adults aged > 65 years, and persons with chronic health conditions.[3] In Mexico and the United States, the percentage of patients requiring hospitalization has been particularly high among persons aged 30–44 years.
Two deaths have been reported in the United States, resulting in a preliminary case-fatality rate of 0.2% among patients with laboratory-confirmed disease. However, such case-fatality rates should be viewed with caution. The actual case-fatality rate is difficult to ascertain in a rapidly evolving outbreak because an unknown proportion of currently infected patients might die, denominators might be uncertain because of unreported cases, and groups at high risk for death from seasonal influenza (e.g., older adults and patients with chronic disease) might not yet have been exposed to the novel influenza A (H1N1) virus.
Summertime influenza outbreaks in temperate climates have been reported in closed communities such as prisons, nursing homes, cruise ships, and other settings with close contact.[4–8] Such outbreaks typically do not result in community-wide transmission, but they can be important indicators of viruses likely to circulate in the upcoming influenza season.[8] The novel influenza A (H1N1) virus has been circulating in North America largely after the peak influenza transmission season. For that reason, the epidemiology and severity of the upcoming influenza season in the southern hemisphere or in the northern hemisphere cannot be predicted. The imminent onset of the season for influenza virus transmission in the southern hemisphere, coupled with detection of confirmed cases in several countries in the southern zone, raise concern that spread of novel influenza A (H1N1) virus might result in large-scale outbreaks during upcoming months. Countries in the southern hemisphere that are entering the influenza season should anticipate outbreaks and enhance surveillance accordingly. Influenza virus can circulate year round in tropical regions; therefore, these countries should maintain enhanced surveillance for novel influenza A (H1N1) virus.
Studies in countries affected by the novel influenza A (H1N1) virus should help guide surveillance, case management, and prevention strategies in countries not yet affected. Key concerns that should be addressed in these studies include assessment of the potential impact on public health; clinical progression of disease, including rates and types of complications for different age and risk groups; and information on virus transmissibility. Assessment of potential disease severity associated with this novel virus will help inform decisions on prevention strategies to slow the spread of infection. Effective control measures will depend on the ability of national governments to quickly gather and share virologic, epidemiologic, and clinical information from multiple sources as new cases appear.
Reported by: General Directorate of Epidemiology, Ministry of Health, Mexico; Pan American Health Organization; World Health Organization; Public Health Agency of Canada; Influenza Div, National Center for Immunization and Respiratory Diseases, CDC Influenza Emergency Response Team, CDC.
* As of May 6, 2009, the number of laboratory-confirmed cases had increased to 1,112.
† Case definition available at http://www.cdc.gov/h1n1flu/casedef.htm.
§ Additional information is available at http://www.who.int/csr/don/2009_05_06.
Published: 08/14/2009
Since mid-April 2009, CDC, state and local health authorities in the United States, the World Health Organization (WHO), and health ministries in several countries have been responding to an outbreak of influenza caused by a novel influenza A (H1N1) virus.[1] In March and early April 2009, Mexico experienced outbreaks of respiratory illness subsequently confirmed by CDC and Canada to be caused by the novel virus. The influenza strain identified in U.S. patients was genetically similar to viruses isolated from patients in Mexico.[2] Since recognition of the novel influenza A (H1N1) virus in Mexico and the United States, as of May 6, a total of 21 additional countries had reported cases, with a total of 1,882 confirmed cases worldwide. Several WHO member states are conducting ongoing investigations of this worldwide outbreak, and WHO is monitoring and compiling surveillance data and case reports. On April 29, WHO raised the level of pandemic alert from phase 4 to phase 5, indicating that human-to-human spread of the virus had occurred in at least two countries in one WHO region. This report provides an update of the initial investigations and spread of novel influenza A (H1N1) virus worldwide.
Mexico
Since implementing enhanced surveillance on April 17, the number of suspected cases has increased rapidly, along with hospitalizations for severe acute respiratory illness (Figure 1). As of May 5, using an updated case definition of fever plus cough or sore throat for a suspected case and real-time reverse transcription–polymerase chain reaction (rRT-PCR) or viral culture for a laboratory-confirmed case, Mexico had identified 11,932 suspected cases and 949* cases of laboratory-confirmed novel influenza A (H1N1) virus infection, including 42 patients who died. Cases with laboratory-confirmed infection have been identified in 27 of 31 Mexican states and the Federal District. Confirmed cases in Mexico and in the United States have a similar age distribution (Table). Information is available on the clinical course of illness for 22 patients with laboratory-confirmed illness who were hospitalized, including seven patients who died. Five of the 15 surviving patients and one of the seven patients who died had underlying chronic medical conditions. Additional details on the clinical signs and symptoms of these and other patients are being collected. Among patients with confirmed cases for whom information was available, 56 (98%) of 57 reported fever, 49 (94%) of 52 reported cough, 23 (79%) of 29 reported dyspnea, 35 (80%) of 44 reported headache, and 34 of (83%) 41 reported rhinorrhea. The government of Mexico has instituted several measures to slow disease transmission and reduce mortality, including closure of all schools and avoidance of large public gatherings, distribution of oseltamivir to all health-care units, publication of specific clinical guidelines, and establishment of a call center to educate members of the public who are seeking health-care information.
United States
After recognition of the first cases of infection with the novel influenza A (H1N1) virus, CDC and state health departments initiated enhanced surveillance measures to identify additional cases. As of May 6, a total of 1,487 confirmed† and probable cases had been reported from 43 states, including 642 confirmed cases (reported from 41 states) and 845 probable cases (reported from 42 states). Current experience with laboratory testing results indicates that the probability of laboratory confirmation for probable cases is > 99%. States with the most confirmed cases are Illinois (122 cases), New York (97), California (67), Texas (61), and Arizona (48). Dates of illness onset for patients with confirmed or probable illness range from March 28 to May 4 (Figure 2), although the most recent case counts do not account for testing and reporting delays. Among persons with laboratory-confirmed illness, 35 hospitalized patients have been reported from 16 states, including two patients from Texas who died, both with underlying medical conditions. The age distribution of persons with laboratory-confirmed disease ranged from 3 months to 81 years (Table). A total of 18 patients were aged < 2 years, and 31 were aged 2–4 years.
The age distribution of the 35 laboratory-confirmed hospitalized patients ranged from 6 months to 53 years (median: 15 years). Among patients with confirmed disease for whom data were available, 262 (90%) of 292 reported fever, 249 (84%) of 296 reported cough, 176 (61%) of 290 reported sore throat, 65 (26%) of 249 reported diarrhea, and 54 (24%) of 221 reported vomiting.
Other Countries
On April 26, the first cases of novel influenza A (H1N1) virus infection outside of the United States and Mexico were reported in Canada. As of May 6, WHO had reported that 309 persons with laboratory-confirmed disease had been identified in 21 countries other than Mexico and the United States. Confirmed cases have been reported from Asia (Hong Kong S.A.R. and Korea), the Pacific region (New Zealand), the Middle East (Israel), Europe, and Central and South America (El Salvador, Costa Rica, Colombia, and Guatemala) (Figure 3).
Of 178 patients for whom travel history was available, 145 (82%) reported recent travel to Mexico, and four (2%) reported travel to the United States. Among those who had not traveled to Mexico, 17 (52%) reported contact with a returning traveler from Mexico. Canada, Germany, Spain, and the United Kingdom all have reported evidence of in-country, second-generation, human-to-human transmission (e.g., a health-care worker in Germany who had cared for a patient with a confirmed infection). No reports have been made of sustained, community-wide transmission in affected countries. Consistent with cases in North America, most of the cases reported from other countries have been among young adults, with a median age of 27.1 years (range: 2–62 years, N = 45). The majority of cases in other countries have been uncomplicated, and no deaths have been reported; four patients have been hospitalized.§
Editorial Note
Early surveillance data from this outbreak suggest that the novel influenza A (H1N1) virus has the potential for efficient, rapid spread among countries. Although the illness associated with infection generally seems self-limited and uncomplicated, a substantial number of cases of severe disease and death has been reported in previously healthy young adults and children. Several characteristics of this outbreak appear unusual compared with a typical influenza seasonal outbreak. First, the percentage of patients requiring hospitalization appears to be higher than would be expected during a typical influenza season.[3] Second, the age distribution of hospitalizations for novel influenza A (H1N1) virus infection is different than that of hospitalizations for seasonal influenza, which typically occur among children aged < 2 years, adults aged > 65 years, and persons with chronic health conditions.[3] In Mexico and the United States, the percentage of patients requiring hospitalization has been particularly high among persons aged 30–44 years.
Two deaths have been reported in the United States, resulting in a preliminary case-fatality rate of 0.2% among patients with laboratory-confirmed disease. However, such case-fatality rates should be viewed with caution. The actual case-fatality rate is difficult to ascertain in a rapidly evolving outbreak because an unknown proportion of currently infected patients might die, denominators might be uncertain because of unreported cases, and groups at high risk for death from seasonal influenza (e.g., older adults and patients with chronic disease) might not yet have been exposed to the novel influenza A (H1N1) virus.
Summertime influenza outbreaks in temperate climates have been reported in closed communities such as prisons, nursing homes, cruise ships, and other settings with close contact.[4–8] Such outbreaks typically do not result in community-wide transmission, but they can be important indicators of viruses likely to circulate in the upcoming influenza season.[8] The novel influenza A (H1N1) virus has been circulating in North America largely after the peak influenza transmission season. For that reason, the epidemiology and severity of the upcoming influenza season in the southern hemisphere or in the northern hemisphere cannot be predicted. The imminent onset of the season for influenza virus transmission in the southern hemisphere, coupled with detection of confirmed cases in several countries in the southern zone, raise concern that spread of novel influenza A (H1N1) virus might result in large-scale outbreaks during upcoming months. Countries in the southern hemisphere that are entering the influenza season should anticipate outbreaks and enhance surveillance accordingly. Influenza virus can circulate year round in tropical regions; therefore, these countries should maintain enhanced surveillance for novel influenza A (H1N1) virus.
Studies in countries affected by the novel influenza A (H1N1) virus should help guide surveillance, case management, and prevention strategies in countries not yet affected. Key concerns that should be addressed in these studies include assessment of the potential impact on public health; clinical progression of disease, including rates and types of complications for different age and risk groups; and information on virus transmissibility. Assessment of potential disease severity associated with this novel virus will help inform decisions on prevention strategies to slow the spread of infection. Effective control measures will depend on the ability of national governments to quickly gather and share virologic, epidemiologic, and clinical information from multiple sources as new cases appear.
Reported by: General Directorate of Epidemiology, Ministry of Health, Mexico; Pan American Health Organization; World Health Organization; Public Health Agency of Canada; Influenza Div, National Center for Immunization and Respiratory Diseases, CDC Influenza Emergency Response Team, CDC.
* As of May 6, 2009, the number of laboratory-confirmed cases had increased to 1,112.
† Case definition available at http://www.cdc.gov/h1n1flu/casedef.htm.
§ Additional information is available at http://www.who.int/csr/don/2009_05_06.
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