Key Flu and RSV Recommendations for the 2024-2025 Respiratory Virus Season

This article originally appeared on Drug Topics®.

A presentation at the National Community Pharmacists Association Annual Meeting and Exposition focused on the latest for vaccination of influenza and respiratory syncytial virus.

Image credit: lungs_PRASANNAPIX

Respiratory virus season is here, according to David Ha, PharmD, BCIDP, but the worst is not yet upon us. The CDC has predicted that this year’s respiratory season is going to look similar—"or maybe slightly less intense”—compared to last year’s season, “but we’ve been fooled before,” Ha said.

At this year’s National Community Pharmacists Association Annual Meeting and Exposition, Ha—Infectious Diseases Manager at Stanford Health Care—provided a comprehensive overview of vaccines for 4 common respiratory viruses and touched on the latest updates from the October 2024 CDC Advisory Committee on Immunization Practices (ACIP) meeting, held just days before the conference.

Influenza

“We haven’t seen influenza season kicking into high gear yet, but that’s certainly going to be coming,” Ha said. “It’s late October; the patients [who] haven’t had their flu shot yet, they should get it ASAP.”

The 2024-2025 flu vaccine has transitioned from a quadrivalent to a trivalent vaccine. “This is an amazing story,” Ha said. “Due to a lot of the COVID-19 interventions, we have eliminated influenza B/Yamagata from circulation; it just hasn’t existed for at least the past season.” This year’s formulation targets the A/H1N1 (Victoria) strain, the A/H3N2 (Thailand) strain, and the B/Austria (Victoria-like lineage) strain.

Ha noted that the influenza vaccine recommendations—largely unchanged by ACIP—are “fairly straightforward”: the CDC still recommends routine vaccination for all individuals aged 6 months or older and individuals aged 65 years or older should preferentially receive a high-dose, adjuvanted, or recombinant vaccine. New for 2024-2025 is the recommendation that individuals who received solid-organ transplants may receive high-dose or adjuvanted vaccines.

“Egg allergy is not a contraindication,” Ha said. “It doesn’t matter what formulation, it doesn’t matter what reaction. The CDC says that you don’t even need additional safety measures; the risk is vanishingly low. It is nearly undetectable because of the infinitesimally small amount of egg protein that is incorporated into these vaccines.”

Self-Administered Influenza Vaccines

New in flu vaccination options is the first and only FDA-approved self- or caregiver-administered flu vaccine, FluMist. This vaccine was approved on September 20, 2024, and is indicated for use in individuals aged 2 to 49 years who are neither pregnant nor immunocompromised. FluMist will not be available for the 2024-2025 flu season but is expected to be available for the 2025-2026 season.

“This is especially exciting for our pediatric patients,” Ha said, a population that can be difficult to vaccinate.

Respiratory Syncytial Virus (RSV)

“I get this a lot from patients: Why is RSV a big deal?” said Ha. “I think this comes from the fact that we’ve talked a lot about COVID, people have heard a lot about influenza, [but] they haven’t heard a lot about RSV. It hasn’t made its way into the news as much as other viruses.”

Despite the lack of public knowledge, RSV vaccination is crucial: on a yearly basis, the vaccine is responsible for between 6000 and 10,000 deaths, 60,000 and 160,000 hospitalizations, and 0.9 to 1.4 million medical encounters, with older adults—especially those living in long-term care facilities or those with cardiopulmonary conditions—are at risk for severe RSV.

Real-world efficacy data, presented at the June 2024 ACIP meeting, “mirrors what we saw in the clinical trials,” Ha said. “This is a fantastically effective vaccine that has quite a bit of durability.”

At the June 2024 meeting, ACIP made the following recommendations for RSV vaccination in older individuals:

• Adults aged 75 years and older who are unvaccinated should receive routine RSV vaccination.
• Adults aged 60 to 74 years who are unvaccinated should receive routine vaccination if they are at high risk for severe disease—for example, those with chronic medical conditions or who live in a nursing home residence or long-term care facility.
• For individuals who were previously vaccinated, no repeat vaccine is indicated.

One common question Ha sees is around the recommendation for adults aged 60 to 74 years who are otherwise healthy. “Based on last season’s recommendations—based on shared clinical decision making—there was an opportunity for those, even without comorbidities, to get vaccinated. That is no longer a CDC recommendation.”

“But what I will say is, this is evolving over time,” Ha added. “CDC is going to be evaluating a broader recommendation for vaccination. I personally would love to see more of a routine recommendation for those that are 60 [years] and older.”

Only 1 RSV vaccine is indicated for use in pregnant women, Pfizer’s bivalent RSV prefusion F RSV vaccine Abrysvo. During the 2023-2024 respiratory virus season, 17.8% of pregnant women aged 18 to 49 were vaccinated, and 51.2% of infants were protected from RSV through either maternal vaccination or administration of nirsevimab.

A common question within this patient population is around the preterm birth signal—which Ha noted “wasn’t ever statistically significant.” Since last season, data have indicated that the incidence of preterm birth in vaccine recipients was within the expected range at 4.1%.

The CDC recommends that pregnant women who are 32 to 36 weeks’ gestational age should receive 1 dose of Abrysvo if not previously received. Administration is seasonal (between September and January in most of the US) and only 1 lifetime dose should be given.