It’s Not Too Late for Influenza Vaccination

Medscape Medical News spoke with the CDC’s Lisa Grohskopf, MD, MPH, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control, about what providers need to know regarding recommendations for influenza vaccination in the United States. 
Text has been edited for length. 
Yes, we have updates to both the vaccine and the vaccine recommendations this year. Typically we have some changes each year, and this year there are two main changes in the recommendations. One relates to the composition of the vaccine for this season, and the other is a new recommendation for adult solid organ transplant recipients. 
We typically have changes in the vaccine composition each season. For most seasons, one or more parts of the vaccine will change, but this year is a little different in that all of the vaccines available in the US for the 2024-2025 season are going to be three-virus, or trivalent, vaccines. They are going to be formulated to protect against three viruses: an influenza A(H1N1) virus, an influenza A(H3N2) virus, and an influenza B/Victoria lineage virus. 
The reason for this change is that since the 2013-2014 season through the 2023-2024 season, we had quadrivalent vaccines that were available in the US that contained four viruses. Those vaccines contained a second influenza B virus from the Yamagata lineage (B viruses come from two main lineages).
The reason for the change to trivalent vaccines this season is that influenza B/Yamagata viruses have not been detected in global surveillance since March 2020, and so their inclusion is no longer warranted. So this season, all of the vaccines available in the US are going to be trivalent.
In addition to that change, we have an update in the influenza A(H3N2) component of the vaccine compared with last season.
The second change concerning adult solid organ transplant recipients is that Advisory Committee on Immunization Practices (ACIP) now recommends that solid organ transplant recipients aged 18-64 years can receive as acceptable options either the high-dose inactivated vaccine or the adjuvanted inactivated vaccine without a preference over other age appropriate, inactivated, or recombinant vaccines.
Those vaccines are both formulated with features intended to make them more immunogenic — ie, promote a stronger immune response — and there are data for immunogenicity that suggest they could be more immunogenic in that population.
That recommendation is the same as it’s been for a number of years, which is that everybody aged 6 months or older is recommended to get a flu vaccine, with some rare exceptions, mainly concerning contraindications to vaccination. 
Contraindications are detailed in the ACIP flu statement each year, and they’re relatively uncommon conditions overall, so most people are recommended, if they’re in that age group 6 months and up, to get an annual flu vaccine.
Yes. While influenza vaccination is recommended for everybody in that age group 6 months and up — and in truth, we can never really predict who’s going to get severely ill — some people are more likely to be at risk of having serious illness or hospitalization. Those people include adults aged 65 years or older; young children; people with certain chronic health conditions such as heart disease, lung disease, and diabetes; and people from some racial and ethnic groups.
Not for most people. In general, we have a number of different influenza vaccines each season; this year we have a total of nine brands. In general, there’s no preferential recommendation for one vaccine or type of vaccine for specific groups of people, with one exception: For people aged 65 years or older, there’s a preferential recommendation for three specific vaccines — the high-dose inactivated vaccine, Fluzone High-Dose; the recombinant vaccine, Flublok; and the adjuvanted inactivated vaccine, FLUAD. 
Among those three, there’s no preference for any one of them over the other two; they’re all preferred vaccines for this age group, if available. If none of those three vaccines are available at the time that somebody aged 65 or older is there to get vaccinated, people in this age group should get any other age-appropriate influenza vaccine that is available.
CDC and ACIP recommend vaccination for most people, ideally by the end of October. But for those who missed the end of October, it is absolutely not too late. Providers should continue to encourage vaccination and people should get their vaccines as long as flu viruses are circulating. 
The timing of the onset and the peak and the end of the flu season vary a bit from year to year. We often start to see generally activity begin to increase in the US in the fall, which is the reason for the end of October recommendation; however, flu activity doesn’t tend to peak in the US until after October. We’re talking December, January, or later, so getting vaccinated after October can still provide important protection during the peak of the season.
There does seem to be a tendency for people to think, OK, I haven’t gotten the vaccine yet, and there probably isn’t a lot of reason to do it now. But really, it’s definitely not too late, and that’s something we like to encourage people to think about, particularly as we move into December and January — it’s not too late if you missed October. 
Influenza vaccination is also available in so many places. You don’t necessarily have to go to a healthcare provider’s office; there are many retail chains which offer influenza vaccines.
Overall influenza activity currently is low nationally, although there’s starting to be some slight increases in the pediatric age groups and, of course, we do anticipate that it will increase in the coming weeks and months.
When we get vaccinated, the protection isn’t instantaneous. The immune system needs a bit of time to react to the vaccine and to develop antibodies. That can take about 2 weeks. Even with that, now is still absolutely not too late to get a vaccine. Neither is December, for that matter. As long as the flu viruses are circulating where you are, it is still worth getting vaccinated.
It’s a little bit early to tell for the current season, but one of the things that we do know is that since the COVID-19 pandemic, coverage has dropped compared with before the COVID-19 pandemic. Before COVID-19, influenza vaccination coverage had been slowly increasing in most groups, but it has decreased since then, and those downturns in coverage haven’t recovered to prepandemic levels. For example, during 2023-2024, about half of children and adults received a flu vaccine. 
We know that a healthcare provider’s strong recommendation for flu vaccination is a really major factor in whether or not patients get a flu vaccine, and is more effective in increasing acceptance of vaccination than just about any other factor. 
There’s a method from CDC called SHARE, which is a helpful way to help make a strong recommendation and provide information to help patients make an informed decision about whether or not they want to be vaccinated.
To implement SHARE, it’s an acronym with five parts. S is for Share the reasons why the flu vaccine is right for that patient. H is for Highlight positive experiences with flu vaccination, either personal or in practice. A is for Address patient concerns and questions about the flu vaccine, including things such as side effects, safety, and effectiveness. R is Remind patients that vaccination protects them and their loved ones from serious illness and related complications. E is Explain the potential complications and consequences of getting influenza, including serious health effects, time lost from family, work, and school, and potential financial costs.
Additional resources are accessible on CDC’s influenza resources page, including brochures, posters, and fact sheets that can help providers in encouraging and reminding people to get vaccinated.
 
Public Information from the CDC and Medscape