The flu vaccine works even when it does not stop you catching flu

Influenza can lead to hospitalisation and sometimes death. In a typical
season, **millions of people get flu, hundreds of thousands are hospitalised,
and thousands to tens of thousands die of flu-related causes.**

**Everyone 6 months and older in the United States, with rare exceptions,
should get a flu vaccine every season.**

The argument people miss

"I got the vaccine and got flu anyway" is the standard objection, and it
treats vaccination as a gate that either holds or fails.

**Several studies have shown that flu vaccination reduces the severity of
illness in people who get flu despite being vaccinated.** The benefit does not
vanish in the year it fails to prevent infection — it changes what the
infection does to you.

Alongside that, vaccination reduces the risk of **flu illness,
hospitalisation, and death from flu-related causes**.

How it works, and how long it takes

Antibodies develop about two weeks after vaccination. That fortnight is
the reason to go before the season rather than during it.

Seasonal vaccines are designed against the influenza viruses research
indicates will be most common in the coming season. **All flu vaccines in the
United States are "trivalent"** — they protect against three viruses:

That holds for the 2026–2027 season: two influenza A viruses and one
influenza B/Victoria virus.

What flu can turn into

Complications include **bacterial pneumonia, ear infections, sinus
infections**, and the worsening of chronic conditions such as congestive
heart failure, asthma or diabetes.

That last category is the one that catches people out. For someone with
asthma or heart failure, the risk is not only the flu itself — it is what the
flu does to the condition they already have.

Choosing a vaccine

Different vaccines are licensed for different age groups, and some are not
recommended for some groups. **For people 65 and older, three flu vaccines are
preferentially recommended** — a specific recommendation rather than a general
one, worth asking about by name.

Source: Centers for Disease Control and Prevention.