It’s very important that children, too, get vaccinated with the current year’s vaccine, since children are less likely to have any residual protection from prior exposure to the flu and are the leading vectors for infecting others should they get sick.
Furthermore, the flu virus is readily transmitted to others starting the day before you develop any telltale signs of the infection, which comes on suddenly. You may be fine in the morning and feel like you’ve been hit by a truck by afternoon. A seemingly healthy child who is incubating the virus can easily transmit it to a dozen others, including teacher and parents, before they know they are sick.
After people who contract the flu think they’re well enough to resume their normal activities, they may continue to spread the virus for up to a week after they first became ill.
growing the virus variants in eggs — can cause them to mutate.
If the variants included in the vaccine differ from those that are ultimately responsible for seasonal outbreaks, protection is likely to be greatly reduced, which is what happened in the 2004-05 and 2014-15 flu seasons, when vaccine effectiveness was only 10 percent and 19 percent, respectively. Last season’s vaccine was about 36 percent effective.
There is also a difference in the protection afforded by the same vaccine given to people in different age categories. For example, the vaccine used against flu in 2012-13 had an overall effectiveness of 49 percent, but was only 11 percent effective for people 65 and older. A higher-potency vaccine is now available for older men and women.
There is now a concerted effort to create a new “universal” flu vaccine that would protect against all manner of variants and not require an annual shot. The goal, Dr. Osterholm said, is “a vaccine that can handle many new changes in the virus and that needs to be given only once every five or 10 years.”
The basic research needed to develop such a vaccine could cost $1 billion a year for the next five to seven years, he estimated. However, Congress allocated a mere $100 million for the coming fiscal year.