How effective is a single dose of H1N1 vaccine for adults?

Originally published in Insidermedicine

Healthy adults require only a single dose of H1N1 vaccine in order to be optimally protected, according to research published in the New England Journal of Medicine.

Here is some information about H1N1 (swine) flu:

• It is a new flu virus that most people have never encountered and therefore have not developed natural immunity to it

• It can cause mild, moderate, or severe illness

• It is spread from person-to-person like a regular flu; it cannot be contracted from eating pork

Researchers from the biopharmaceutical company CSL Limited in Australia randomly assigned 240 healthy adults to receive two doses of either 15 mcg or 30 mcg of the H1N1 vaccine. Their immune response was measured before vaccination and again 21 days afterward.

By the 21st day following the first vaccination, 95% of those who received the 15 mcg dose and 89% of those who received the 30 mcg dose of the vaccine had developed an adequate number of antibodies to the H1N1 virus. The second vaccination did not increase their immunity to this virus. There were no deaths or serious adverse events in response to the vaccination, although just over half of the participants reported soreness at the injection site.

Today’s research demonstrates that there is no need for healthy adults to have more that one dose of the H1N1 vaccine in order to be protected from the H1N1 flu.

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