Monday, August 3, 2009

ACIP Issues Targeted Recommendations for H1N1 Vaccinations This Fall

Pregnant women and young children should go to the front of the line when vaccine for the novel influenza A (H1N1) virus becomes available in the fall, according to the CDC's Advisory Committee on Immunization Practices, or ACIP.
During a July 29 emergency meeting convened to address issues surrounding the H1N1 virus, ACIP recommended that vaccination efforts focus on five key populations:
  • pregnant women,
  • people who live with or care for children younger than 6 months of age,
  • health care and emergency services personnel,
  • individuals 6 months to 24 years of age, and
  • people ages 25 to 64 years who are at increased risk from novel H1N1 because of chronic health conditions or compromised immune systems.
As of July 24, the CDC said there were 43,771 confirmed or probable H1N1 cases in the United States, with more than 5,000 hospitalizations and 302 deaths linked to the outbreak. Patients ages 5 to 24 years have the highest incidence of infection, and children from birth to 4 years of age have the highest rate of hospitalization.

The CDC said that targeting the aforementioned groups should help reduce the impact and spread of the novel virus. The targeted populations include people who are at higher risk of disease or complications, those who are likely to come in contact with novel H1N1, and those who could infect infants.

"Children under 6 months are not able to be vaccinated directly," said Anne Schuchat, M.D., director of the CDC's National Center for Immunization and Respiratory Diseases, during a July 29 media briefing"And because they can't be directly protected, the public health strategy is to protect those around them to keep from spreading the virus to them."

A recent report in The lanced detailed the high risks for pregnant women associated with the virus. According to that report, of 34 confirmed or probable cases of H1N1 infection in pregnant women reported to the CDC between April 15 and May 18 of this year, six proved fatal. All six deaths occurred in women who had developed pneumonia and subsequent acute respiratory distress syndrome requiring mechanical ventilation.

Schuchat said pregnant women have been disproportionately affected by the novel virus and are four times more likely to be hospitalized compared with members of the general population who are infected.

She also reiterated that health care workers should receive the H1N1 vaccine and the seasonal flu vaccine to protect themselves, their patients and their colleagues.

The targeted groups account for about 159 million people, or more than half the nation's population. Meanwhile, CDC experts told ACIP that the agency expects there to be 120 million doses of the vaccine -- which likely will need to be administered as a two-dose series -- by October. Another 80 million doses are expected to become available each month thereafter.

Although the number of estimated doses available in October doesn't equal the number of people recommended for vaccination, the shortfall might not be an issue. Schuchat said seasonal influenza vaccine is recommended for 83 percent of the population, but less than 40 percent of Americans receive the vaccine each year.

The CDC said it does not anticipate a shortage of H1N1 vaccine, but in the event that vaccine supply is limited, ACIP members recommend that the following groups receive the vaccine before others:
  • pregnant women,
  • people who live with or care for children younger than 6 months of age,
  • health care and emergency services personnel with direct patient contact,
  • children 6 months to 4 years, and
  • children 5 to 18 years who have chronic medical conditions.
The smaller, prioritized groups would include about 42 million people, CDC officials said.

"I expect those priority groups to disappear pretty quickly based on demand," said Doug Campos-Outcalt, M.D., M.P.A., the AAFP's liaison to ACIP and associate head of the department of family and community medicine at the University of Arizona College of Medicine, Phoenix. "The public doesn't perceive this disease to be serious. I think there will be vaccine pretty quickly for anyone who wants it."

Meanwhile, ACIP recommends that physicians and other clinicians begin offering seasonal flu vaccinations as soon as possible. Seasonal flu vaccine typically is administered in the fall, but the CDC is pushing for an early start to immunizations to make room for H1N1 immunizations when the vaccine becomes available.

"You don't need to wait to give that shot," Campos-Outcalt said of seasonal flu vaccine. "You can give it now, and immunity will last through the flu season."

Schuchat said it's likely that seasonal flu vaccine and H1N1 vaccine can be given during the same visit, and that is one of many issues that will be addressed during clinical trial that now are getting under way.

In related news, the FDA announced this week that it had issued an emergency use authorization, or EUA, for the Focus Diagnostics Influenza H1N1 (2009) Real-Time Reverse Transcription Polymerase Chain Reaction (RT-PCR) diagnostic test. It is the third diagnostic test authorized under an EUA since a public health emergency regarding the H1N1 virus was declared in April.

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