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.