H1N1 Vaccine Clinical Trials in Adults Free of Serious Adverse Events

No serious adverse events have been reported during the first two weeks of clinical trials involving vaccine against the novel influenza A (H1N1) virus, according to federal officials.

"There are no 'red flags' regarding safety," said Anthony Fauci, M.D., director of the NIH's National Institute of Allergy and Infectious Diseases, during an Aug. 21 media briefing. "In fact, the trigger to go ahead with the pediatric trial about 10 to 14 days after the adult (and) elderly trials was our data and safety monitoring board looking at the adverse events, which were essentially none."

Although there have been incidences of swelling and pain at the injection site, which, Fauci noted, is seen with almost every vaccine, there have been no serious adverse events.

Fauci detailed the clinical trials during a joint media briefing with officials from the CDC and the FDA. He said clinical trials with adults and the elderly started Aug. 7 and are examining whether the vaccine should contain 15 mg or 30 mg of antigen, as well as whether one or two doses would be needed to provide adequate protection. The clinical trials also will determine whether the new vaccine should be given before, after or at the same time as seasonal flu vaccine.

Fauci said both the adult and elderly trials are fully enrolled. Data derived from participants who have received the first dose is expected to be available in mid-September, with second-dose data available in mid-October.

On Aug. 19 and 20, similar trials began in children ages 6 months to 17 years. Fauci said first-dose data from those trials should be available by late September, with second-dose data expected in late October.

Trials involving pregnant women are scheduled to begin in early September, and trials involving the use of adjuvants are expected to start in mid- or late September.

Pregnant women, children ages 6 months to 4 years, and those ages 5 to 18 who have chronic medical conditions are among the groups prioritized to receive the H1N1 vaccine when it becomes available commercially.

CDC officials said in late July that the agency hoped to have 120 million doses of H1N1 vaccine available by October, but federal officials now expect only about 45 million doses to be available by mid-October because of manufacturing issues. Twenty million more doses should be available each week thereafter.

About 42 million people are included in the top priority groups, which also include people who live with or care for children younger than 6 months of age and health care and emergency services personnel who have direct patient contact.

Jesse Goodman, M.D., M.P.H., acting chief scientist and deputy commissioner for scientific and medical programs at FDA, said during the Aug. 21 media briefing that the agency has provided new vaccine strains to manufacturers in an attempt to improve yields.

When vaccine becomes more widely available, the CDC's Advisory Committee on Immunization Practices, or ACIP, has recommended that people in the following groups receive the vaccine:

ACIP members made their provisional recommendations at a July 29 emergency meeting in Atlanta. The CDC published the recommendations in an Aug. 21 Morbidity and Mortality Weekly Report.

The CDC estimates that more than 1 million Americans have been infected with the novel virus to date. As of Aug. 21, nearly 8,000 laboratory-confirmed hospitalizations and 522 deaths in the United States had been reported.