Prevent Swine Flu

H1N1 Vaccine – Jury is still out

Teens and young adults continue to account for the majority of cases of H1N1 around the world, with numbers of hospitalized cases highest in very young children. One% to ten% of patients with clinical illnesses will require hospitalization. Of those hospitalized patients anywhere from 10% to 25% will need to be admitted to an intensive care unit. Of those cases, 2% to 9% end up being fatal.  This information is according to the Strategic Advisory Group of Experts (SAGE) on Immunization, which advises the World Health Organization (WHO) on policies and strategies for vaccines and immunization.

A recent session of the SAGE October 27^th – 29^th meeting was dedicated to the discussion of pandemic influenza vaccines. The experts at SAGE reviewed the current epidemiological situation of the pandemic worldwide and considered issues and options from a public health perspective. Overall, from 7% to 10% of all hospitalized patients are pregnant women in their second or third trimester of pregnancy. Pregnant women are ten times more likely to need care in an intensive care unit when compared with the general population.  Based on data and the substantially elevated risk for a severe outcome in pregnant women infected with the pandemic virus, The Strategic Advisory Group of Experts on Immunization (SAGE) recommended that any licensed vaccine can be used in pregnant women, provided no specific opposition has been identified by the regulatory authority.

The SAGE experts also advised WHO on the number of doses of vaccine needed to provide protection across all different age groups, the joint dispensing of seasonal and pandemic vaccines, and vaccines for use in pregnant women. Recommendations on the formulation of seasonal influenza vaccines for the southern hemisphere in 2010 were also provided.  Other agenda items discussed included the status of vaccine availability, results from clinical trials on vaccine immunogenicity, and early results from safety monitoring in countries where dispensation of the H1N1 pandemic vaccine is currently under way.

Early results of the monitoring of people who have received pandemic vaccines were reviewed by the experts from SAGE and there were no indications of unusual adverse reactions found. Some adverse events following vaccination have been noticed, but these are well within the range of those seen with seasonal vaccines. All of which are believed to have an excellent safety profile.  Although early results are encouraging, they suggested monitoring for adverse events should be continued. The group also suggested that data on immunogenicity in children older than 6 months and younger than 10 years are limited and more studies are needed. National authorities have made children a priority for early vaccination. The SAGE recommendation is that precedence be given to the allocation of one dose of vaccine to as many children as possible.

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