Is Flu, COVID-9 Vaccine Co-Administration in Pharmacists’ Future?

Although it initially recommended against it, a CDC panel had approved co-administration of vaccines in general with COVID-19 shots. Now, ACIP says co-administration with seasonal flu vaccines also is okay. Find out what that might mean for pharmacists who offer immunizations.

ATLANTA – Come influenza vaccination season, there is a good chance that pharmacists and other immunizers will be co-administering influenza and COVID-19 vaccines or boosters, based on actions by a national Centers for Disease Control & Prevention advisory group.

In a unanimous 14-0 vote, the CDC’s Advisory Committee on Immunization Practices approved language for co-administration of influenza and COVID-19 vaccines. CDC guidance already allows COVID-19 vaccines to be administered with other vaccines. It cautions, however, that healthcare providers should be aware of increased reactogenicity.

The decision was at least partly based on a study published as a preprint in June by MedRxiv. The Novavax Inc.-led researchers point out that the safety and immunogenicity profile of COVID-19 vaccines administered concomitantly with seasonal influenza vaccines had not been established. The study team conducted a sub-study on influenza vaccine co-administration as part of the Novavax NVX-CoV2373 COVID-19 vaccine safety and efficacy trial.

To do that, researchers invited the first about 400 participants meeting main study entry criteria and with no contraindications to influenza vaccination to join the sub-study. The group was randomized in a 1:1 ratio to receive NVX-CoV2373 or placebo, with sub-study participants receiving an age-appropriate, licensed, open-label influenza vaccine with the first dose of NVX-CoV2373.

To evaluate reactogenicity, participants provided information through an electronic diary for 7 days post-vaccination, while also monitoring for unsolicited adverse events (AEs), medically-attended AEs (MAAEs), and serious AEs (SAEs). In addition, researchers performed influenza haemagglutination inhibition and SARS-CoV-2 anti-spike IgG assays to access vaccine efficacy against PCR-confirmed, symptomatic COVID-19. Comparisons then were made between main study participants and sub-study participants, who tended to be

younger, more racially diverse, and had fewer comorbid conditions.

Results indicate that reactogenicity events more common in the co-administration group included:

  • tenderness (70.1% vs 57.6%) or pain (39.7% vs 29.3%) at injection site,
  • fatigue (27.7% vs 19.4%), and
  • muscle pain (28.3% vs 21.4%).

“Rates of unsolicited AEs, MAAEs, and SAEs were low and balanced between the two groups,” the authors advise. “Co-administration resulted in no change to influenza vaccine immune response, while a reduction in antibody responses to the NVX-CoV2373 vaccine was noted. Vaccine efficacy in the sub-study was 87.5% (95% CI: -0.2, 98.4) while efficacy in the main study was 89.8% (95% CI: 79.7, 95.5).”

Researchers point out that the study was the first to demonstrate the safety, immunogenicity, and efficacy profile of a COVID-19 vaccine when co-administered with seasonal influenza vaccines, adding, “The results suggest concomitant vaccination may be a viable immunization strategy.”

CDC’s guidance on co-administration already had changed before the ACIP vote. “COVID-19 vaccines were previously recommended to be administered alone, with a minimum interval of 14 days before or after administration of any other vaccines,” according to its website. “his was out of an abundance of caution and not due to any known safety or immunogenicity concerns. However, substantial data have now been collected regarding the safety of COVID-19 vaccine currently authorized by FDA for use under EUA.”

The guidance explains that, while little data is available for COVID-19 vaccines administered simultaneously with other vaccines, “extensive experience with non-COVID-19 vaccines has demonstrated that immunogenicity and adverse event profiles are generally similar when vaccines are administered simultaneously as when they are administered alone.”

The result is guidance suggesting that COVID-19 vaccines and other vaccines can now be administered without regard to timing. That includes simultaneous administration of COVID-19 vaccine and other vaccines on the same day, as well as coadministration within 14 days.

On the other hand, public health officials say it is not known whether reactogenicity of COVID-19 vaccine is increased with coadministration, which might especially be a problem with vaccines known to be more reactogenic, such as adjuvanted vaccines or live vaccines.

“When deciding whether to coadminister another vaccine(s) with COVID-19 vaccine, vaccination providers should consider whether the patient is behind or at risk of becoming behind on recommended vaccines, their risk of vaccine-preventable disease (e.g., during an outbreak or occupational exposures), and the reactogenicity profile of the vaccines,” the guidance notes.

The CDC further advises that, if multiple vaccines are administered at a single visit, administer each injection in a different injection site.

Best practices for multiple injections include:

  • Labeling each syringe with the name and the dosage of the vaccine, lot number, the initials of the preparer, and the exact beyond-use time, if applicable.
  • Separating injection sites by 1 inch or more, if possible.
  • Administering the COVID-19 vaccines and vaccines that may be more likely to cause a local reaction -- including tetanus-toxoid-containing and adjuvanted vaccines -- in different limbs, if possible.

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