The Medical Letter on Drugs and Therapeutics
COVID-19 Updates
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Med Lett Drugs Ther. 2022 Apr 18;64(1648):63-4
Principal Faculty
  • Mark Abramowicz, M.D., President: no disclosure or potential conflict of interest to report
  • Jean-Marie Pflomm, Pharm.D., Editor in Chief: no disclosure or potential conflict of interest to report
  • Brinda M. Shah, Pharm.D., Consulting Editor: no disclosure or potential conflict of interest to report
Additional Contributor(s)
  • Michael Viscusi, Pharm.D., Associate Editor: no disclosure or potential conflict of interest to report
Upon completion of this activity, the participant will be able to:
  1. Describe the recommendations on the second booster vaccine dose for older and immunocompromised persons and the FDA restriction on the use of sotrovimab.
 Select a term to see related articles  bebtelovimab   Comirnaty   COVID-19   Lagevrio   molnupiravir   nirmatrelvir   Paxlovid   remdesivir   Ritonavir   sotrovimab   Spikevax   vaccines   Veklury 

Second Booster Vaccine Dose for Older and Immunocompromised Persons

The FDA has expanded the Emergency Use Authorizations (EUAs) for the mRNA COVID-19 vaccines manufactured by Pfizer-BioNTech (Comirnaty) and Moderna (Spikevax) to allow for their use as a second booster dose ≥4 months after a first booster dose in adults ≥50 years old and in persons aged ≥12 years (Pfizer) or ≥18 years (Moderna) who have undergone solid organ transplantation or have a condition that compromises the immune system to a similar extent.1,2

EFFICACY — Expansion of the EUAs was based on the results of a cohort study in healthcare workers in Israel who had received two primary doses and one booster dose of the Pfizer COVID-19 vaccine ≥4 months previously. A total of 274 persons were boosted again with either the Pfizer vaccine (n=154) or the Moderna vaccine (n=120) and then compared with age-matched controls over ~34 days (Pfizer) or ~25 days (Moderna). Geometric mean titers of neutralizing anti-SARS-CoV-2 antibodies 2 weeks after a second booster dose were significantly higher than those in the control group (by 10.4-fold with Pfizer and by 14.3-fold with Moderna) and slightly higher than those observed 2 weeks after the first booster dose (by 1.4-fold with Pfizer and by 2.0-fold with Moderna). The rate of symptomatic COVID-19 from day 8 was lower in persons who received a second booster dose than in those who did not (by 43% [95% CI 7% to 65%] with Pfizer and by 31% [95% CI -18% to 60%] with Moderna).3

In a 40-day retrospective cohort study in 563,735 persons 60-100 years old in Israel, the rate of death due to COVID-19 was significantly lower in persons who received a second COVID-19 vaccine booster dose during the study period than in eligible persons who did not (28 vs 99 deaths per 100,000 persons; adjusted HR 0.22 [95% CI 0.17-0.28]).4

SAFETY — In the cohort study in healthcare workers, adverse effects with a second booster dose were similar to those with previous vaccine doses.2 According to the FDA, a surveillance study (not published) of ~700,000 persons in Israel who received a fourth dose of the Pfizer vaccine did not generate new safety concerns.1

DOSAGE — The recommended second booster doses of the mRNA vaccines are the same as the initial booster doses (30 mcg for Pfizer; 50 mcg for Moderna). A second booster dose can be given ≥4 months after an initial booster dose of any FDA-authorized or approved COVID-19 vaccine (Pfizer, Moderna, or Johnson & Johnson/Janssen).5,6

FDA Restricts Use of Sotrovimab

The FDA has begun to restrict use of the anti-SARS-CoV-2 monoclonal antibody sotrovimab in US regions with a high relative prevalence of the BA.2 (Omicron) variant of the virus.1 Sotrovimab, which is available under an Emergency Use Authorization (EUA) for treatment of mild to moderate COVID-19 in high-risk patients ≥12 years old who weigh ≥40 kg,2 is unlikely to be effective for treatment of COVID-19 caused by BA.2; it has significantly less neutralizing activity in vitro against BA.2 than against other variants.3

Sotrovimab is no longer authorized for use in regions where the BA.2 variant of SARS-CoV-2 causes >50% of COVID-19 cases. At the time of publication (March 31, 2022), this was the case in HHS Regions 1 (New England), 2 (NJ, NY, Puerto Rico, Virgin Islands), 5 (Upper Midwest), 9 (AZ, CA, HI, NV, Pacific islands), and 10 (AK, ID, OR, WA).1 BA.2 is likely to become the predominant strain of SARS-CoV-2 in all regions of the US in the coming weeks4; announcements of further restrictions on use of sotrovimab will be published at: Alternative treatments for mild to moderate COVID-19 that retain efficacy against the BA.2 variant include nirmatrelvir/ritonavir (Paxlovid), remdesivir (Veklury), bebtelovimab, and molnupiravir (Lagevrio).5

Additional Content Available Online: COVID-19 Tables/Charts
See the latest information on COVID-19, including our continuously updated tables/charts on treatments, vaccines, and dosing recommendations.

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