Academic OB/GYN

New data is being published in the upcoming issue of the New England Journal of Medicine on the immune response associated with the new Novel H1N1 Flu Vaccine, and in the interest of public health it has already been distributed on the web.

Three articles will be published, two on the ability of various dosages of the vaccine to create an immune response, and a third on the presence of immune antibodies in people exposed to previous seasonal flu vaccines, and to past outbreaks of natural H1N1 “swine” flu.

The bottom line:

1) A single 15 microgram dose of the novel H1N1 vaccine creates an adequate immune response in near 100% of people within 14 days of administration.  There will be no need to have a second shot.   CDC guidelines will likely be changed to reflect this.

2) People who were immunized to the seasonal flu last year in the Northern Hemisphere have no or low chance of having immunity to Novel H1N1 (swine) flu.   People who were immunized with the southern hemisphere vaccine last year have some chance of immunity, but still should get the new vaccine this year.

3) People who were exposed to previous pandemic flu strains often have resistance to this pandemic flu.   Today’s novel H1N1 pandemic flu strain is likely related to the flu strains that caused outbreaks in 1918 and 1976.  Older patients are more likely to have been exposed to one of these outbreaks and be immune today.   Still, there are enough people in that age group that are not immune (higher than 50% in many cases) that all people should be immunized if possible.

Sources:

Response after One Dose of a Monovalent Influenza A (H1N1) 2009 Vaccine — Preliminary Report.  Greenberg ME, Lai MH, Hartel GF, Wichems CH, Gittleson C, Bennet J, Dawson G, Hu W, Leggio C, Washington D, Basser RL.N Engl J Med.  2009 Sep 10.

Trial of Influenza A (H1N1) 2009 Monovalent MF59-Adjuvanted Vaccine — Preliminary Report.  Clark TW, Pareek M, Hoschler K, Dillon H, Nicholson KG, Groth N, Stephenson I.  N Engl J Med. 2009 Sep 10.

Cross-Reactive Antibody Responses to the 2009 Pandemic H1N1 Influenza Virus.  Hancock K, Veguilla V, Lu X, Zhong W, Butler EN, Sun H, Liu F, Dong L, Devos JR, Gargiullo PM, Brammer TL, Cox NJ, Tumpey TM, Katz JM. N Engl J Med. 2009 Sep 10.