Need a flu shot? Get it now

I have often heard people refuse the vaccine because they have had flu-like symptoms after the injection or have caught the flu in spite of it.

The facts: 1) The vaccine does not cause and can not cause the flu. Either they were infected before vaccination or before immunity, or the fever and pain they felt were the side effects of the vaccination, not the flu itself. 2) In its current formulation, the vaccine is far from perfect. In some years, the effectiveness of influenza prevention has been only 20%, although it can still reduce the severity of the disease and the likelihood of complications.

The main problem with the influenza vaccine is the need to determine, several months before the influenza season, which virus variants to include. The influenza virus is a moving target that is very vulnerable to mutations. Even the way the vaccine is made – often involving the growth of virus variants in eggs – can cause them to mutate.

If the variants included in the vaccine differ from those ultimately responsible for seasonal epidemics, protection will likely be significantly reduced, as was the case during the 2004-05 and 2014-15 influenza seasons, while the efficacy of vaccine was only 10%. 19 percent, respectively. The vaccine last season was effective at about 36%.

There is also a difference in the protection offered by the same vaccine administered to people of different age groups. For example, the influenza vaccine used in 2012-13 had an overall efficacy of 49%, but only 11% in people 65 years and older. A more powerful vaccine is now available for men and older women.

A concerted effort is now underway to create a new "universal" influenza vaccine that would protect against all sorts of variants and would not require an annual vaccine. According to Mr Osterholm, the goal is "a vaccine that can handle many changes in the virus and should only be administered once every five or ten years".

The basic research needed to develop such a vaccine could cost $ 1 billion a year for the next five to seven years, he said. However, Congress has only allocated $ 100 million for the next fiscal year.