CDC Considering Early Start to Seasonal Flu Vaccinations

Physicians and other health care professionals might be giving vaccinations for seasonal influenza well in advance of the flu season this year.

Daniel Jernigan, M.D., M.P.H., deputy director of the CDC's Influenza Division, said during a May 20 media briefing that the agency is considering an early rollout of the seasonal influenza vaccine in the hope that a vaccine for the novel H1N1 influenza will be ready in the fall.

Development and approval of a combination product containing both vaccine for the novel H1N1 virus and the seasonal influenza vaccine by fall is unlikely, which means that physicians, hospitals and public health agencies will need time to vaccinate people against both seasonal flu and the H1N1 virus. In fact, the Strategic Advisory Group of Experts on Influenza A H1N1 Vaccines at the World Health Organization, or WHO, said May 18 that a combination vaccine would have significant regulatory implications, and therefore, production of a monovalent H1N1 vaccine is the preferred option.

Jernigan said production of the seasonal influenza vaccine is nearly complete, but he did not specify how far forward the agency hopes to move the start of vaccinations, which typically begin in October.

He did say, however, that the CDC hopes to send vaccine viruses for H1N1 to manufacturers by the end of May.

Meanwhile, vaccine manufacturer GlaxoSmithKline said May 15 that it already has orders for more than 125 million doses of H1N1 vaccine from various European governments, although it is waiting for the WHO to provide the virus.

The WHO said May 22 that there were 11,168 laboratory confirmed cases of novel H1N1 in 42 countries with 86 confirmed deaths. The CDC said May 21 there were 5,764 probable or confirmed cases in 48 states, including nine deaths in six states. There were 249 known hospitalizations linked to the outbreak in 35 states.

In other news, the CDC released a Morbidity and Mortality Weekly Report, or MMWR, on May 18 that analyzed 30 confirmed or probable H1N1 cases at California hospitals. Sixty-four percent of the patients had underlying medical conditions, including chronic lung disease, chronic cardiac disease, diabetes, obesity and conditions associated with immunosuppression. Nationwide, the CDC said May 21 that 71 percent of hospitalized patients had underlying chronic medical conditions.

Obesity had not previously been identified as a high-risk factor for complications.

"We were surprised by the frequency of obesity among the severe cases that we've been tracking," said Anne Schuchat, M.D., interim deputy director for the CDC's Science and Public Health Program, in a May 19 press briefing. "I do think it's an important result. The question of whether people with obesity need to be treated differently in terms of anti-viral treatment or seasonal flu vaccinations is one we're looking into."

Pregnancy had been previously identified a high-risk factor for complications, and five of the 30 California patients were pregnant. Two developed complications.

In addition, Schuchat said 29 of the 30 patients presented with fevers. Other common symptoms were cough, shortness of breath and vomiting. None of the patients had died as of May 19.

According to Schuchat the prevalence of vomiting was unusual compared to seasonal influenza. That is just one way the new virus differs from the seasonal flu. H1N1 has largely affected younger people while leaving older populations relatively unscathed.

The CDC said in its May 22 MMWR that adults, especially those 60 and older, may have some degree of pre-existing immunity to the novel H1N1 virus. This immunity may arise because of previous exposure -- involving either infection or vaccination -- to an influenza A (H1N1) virus that is more closely related to the novel influenza H1N1 virus than to contemporary strains of seasonal H1N1.

The MMWR also reports that children have little or no immunity to the novel H1N1 virus, and the seasonal influenza vaccine is unlikely to provide protection against the new virus.

Schuchat stressed that the CDC still recommends seasonal influenza vaccinations for protection against those viruses.