# 3237
Yesterday Dr. Dan Jernigan of the CDC gave us a heads up that we would be seeing a new serological study on possible partial immunity against the H1N virus in those born before 1957.
Today the MMWR (Morbidity & Mortality Weekly Report) brings us a study entitled:
Yes, the title is a mouthful, and the report is long and fairly technical. Luckily, at the end they do summarize their findings, and I’ve extracted the highlights below:
- The results in this report suggest that vaccination with recent (2005--2009) seasonal influenza vaccines is unlikely to provide protection against the novel influenza A (H1N1) virus.
- Although vaccination of adults with seasonal TIV generally resulted in a small increase in antibodies against the novel influenza A (H1N1) virus, whether such levels of cross-reactive antibody provide any protection against infection with novel influenza A (H1N1) virus is unknown.
- Results indicate that U.S. children are largely serologically naïve to the novel influenza A (H1N1) virus and that vaccination with seasonal TIV or LAIV does not elicit any measurable level of cross-reactive antibody to the novel virus.
- Results among adults suggest that some degree of preexisting immunity to the novel H1N1 strains exists, especially among adults aged >60 years.
- Development of a strain-specific vaccine against the novel influenza A (H1N1) virus is needed for optimal protection against the virus among persons of all ages.
So, to review.
The vaccines used over the past 5 years provide no demonstrable protection against this new H1N1 swine flu virus in laboratory testing.
Some older adults may have, due to previous flu vaccinations or exposure to other H1N1 viruses, some small amount of antibody protection against this virus, but it isn’t clear whether it is enough to make a clinical difference.
Children, on the other hand, seem to have little or no acquired immunity to this virus.
Adults over 60 may have a higher degree of antibody protection than younger adults – perhaps due to exposure to a genetically similar virus - but once again, it isn’t clear how protective that response might be.
The last point in the bullet list sums it up pretty well.
Development of a strain-specific vaccine against the novel influenza A (H1N1) virus is needed for optimal protection against the virus among persons of all ages.
