COVID-19 Roundup: Booster Recommendations, Antiviral Pill, Immunity After Booster Dose

Updated Booster Recommendations¹

The Centers for Disease Control and Prevention have expanded its COVID-19 booster vaccine recommendations to include additional populations.

This updated recommendation follows the recent spread of a new, highly transmissible variant, omicron (B.1.1.529).

All individuals aged 18 years or older are now eligible for a booster dose. Booster doses cannot be administered until 6 months after completion of a patient’s primary series for Pfizer or Moderna COVID-19 vaccines, or 2 months after his or her initial Johnson & Johnson vaccine.  

Panel Recommends Antiviral Pill²

A panel of health advisers from the US Food and Drug Administration (FDA) voted 13 to 10 to recommend the use of the first antiviral COVID-19 pill, molnupiravir.

After weighing the benefits and safety concerns, the panel recommends the use of the antiviral therapy in adults with mild to moderate COVID-19 who are high-risk, such as individuals with obesity or asthma. The panel emphasized that molnupiravir should not be prescribed to individuals who are pregnant, as there is a potential risk of birth defects. Further, the panel recommends the use of extra precautions such as pregnancy tests for women of child-bearing age. The panel does not recommend the antiviral for vaccinated individuals, as vaccinated individuals were not included in the clinical trials.

The antiviral is taken orally, twice per day for 5 days. There is insufficient data on the effectiveness of this treatment against the latest COVID-19 variant, omicron.

Molnupiravir, produced by Merck, was recently approved for use in the United Kingdom. The US FDA is expected to make its recommendation on the use of molnupiravir before the end of the year.

Infection Following 3 COVID-19 Vaccine Doses³

A third dose of the Pfizer-BioNTech (BNT162b2) COVID-19 vaccine decreased the odds of testing positive for SARS-CoV-2 compared with 2 doses of the Pfizer-BioNTech vaccine, according to the results of a recent study.

Included were 306,710 individuals aged 40 years or older from Maccabi Healthcare Services in Israel from March 2020 to October 2021. Among those with 2 doses of the vaccine, 227,380 polymerase chain reaction (PCR) tests were performed, of which 6.6% (n = 14,989) had a positive result. In comparison, for those with 3 doses of the vaccine, 272,852 tests were performed, of which 1.8% (n = 4941) had a positive result. In the 28 to 65 days following receipt of the booster, there was an estimated odds ratio of 0.14 when comparing the 2 groups.

“Previous studies have demonstrated that vaccine-derived protection against SARS-CoV-2 wanes over time,” the researchers concluded. “In this case-control analysis, we showed an association between receipt of the booster dose and a reduction in the odds of testing positive for SARS-CoV-2, potentially counteracting waning immunity in the short term. Further monitoring of data from this population is needed to determine the duration of immunity following the booster.”

—Leigh Precopio