COVID-19 Roundup: Bivalent Booster Authorizations, PrEP Updates, and Myocardial Infarctions Rates

FDA Approves COVID-19 Single-Dose Bivalent Booster Vaccines for Younger Age Groups1

The FDA updated the emergency use authorization of the Moderna vaccine bivalent booster and the Pfizer-BioNTech vaccine bivalent booster, authorizing the single booster dose to prevent COVID-19 in younger age groups.

A bivalent COVID-19 vaccine includes a component of the original virus strain and a component of the omicron variant, creating protection against both strains of COVID-19.2

The Moderna bivalent vaccine has been authorized for administration following at least 2 months of primary or booster vaccination in children as young as 6 years of age. The Pfizer-BioNTech bivalent has been authorized for administration following at least 2 months of primary or booster vaccination in children as young as 5 years of age.

With the authorization, the monovalent Pfizer-BioNTech vaccine is no longer authorized as a booster for children aged 5 to 11 years.

“Since children have gone back to school in person and people are resuming pre-pandemic behaviors and activities, there is the potential for increased risk of exposure to the virus that causes COVID-19. Vaccination remains the most effective measure to prevent the severe consequences of COVID-19, including hospitalization and death,” said Peter Marks, MD, PhD, the director of the Center for Biologics Evaluation and Research at the FDA in a press release.

COVID-19 Pre-Exposure Prophylaxis Treatment Increases Risk of Developing Virus3

Tixagevimab co-packaged with cilgavimab (Evusheld), the only option for pre-exposure prophylaxis (PrEP) of COVID-19, increases the risk of individuals developing COVID-19 when exposed to variants that are not neutralized by the medication, according to the FDA.

It is recommended that health care professionals inform their patients of the risk and that if symptoms of COVID-19 begin to develop, patients should get tested for the virus as soon as they can. Medical treatment should be started immediately upon a positive test result.

The information is an addition to the tixagevimab with cilgavimab fact sheet provided by the FDA. The use of the COVID-19 PrEP does not substitute the vaccination, but the treatment is still recommended and authorized for use in patients who are immunocompromised that may not fully benefit from the COVID-19 vaccine.

“FDA continues to recommend tixagevimab with cilgavimab as an appropriate option for PrEP to prevent COVID-19, in combination with other preventative measures like getting vaccinated and boosted as recommended, as tixagevimab with cilgavimab still offers protection against many of the currently circulating variants and may offer protection against future variants,” the FDA wrote in a press release.

Rate of Myocardial Infarctions Rose During Pandemic Surges4

A substantial increase in acute myocardial infarctions (AMI) was observed during COVID-19 surges, according to a recent study.

The researchers aimed to assess the extent and disparity in AMI-associated mortality, including the omicron variant outbreak (October 2021 to March 2022). The researchers looked at the excess death—the difference between the observed and the predicted mortality rates—of AMI.

Using the CDC’s National Vital Statistics System, the researchers identified 1,522,669 AMI-associated deaths that occurred between April 2012 and March 2022 and compared age-related mortality rates pre- and post-pandemic. Before the pandemic, the researchers examined a decrease in AMI-associated deaths across all subgroups. But during the omicron surge, the researchers examined a spike in deaths, specifically in youngest-aged females and males.

“The trend of mortality suggests that age and sex disparities have persisted even through the recent omicron surge, with excess AMI-associated mortality being most pronounced in younger-aged adults,” the researchers concluded.

Omicron Subvariants Likely Resistant to COVID-19 Antibodies Treatment5

According to a report by the CDC, there is a rapid increase in omicron subvariants in the United States. Certain omicron subvariants may likely be resistant to COVID-19 monoclonal antibodies (mAbs) that help treat the virus.

The subvariants BQ.1 and BQ.11 may be resistant to bebtelovimab, and the subvariants BA.4.6, BA2.75.2, BF.7, BQ.1, and BQ.1.1 are likely to be resistant to tixagevimab plus cilgavimab (Evusheld).

Despite the resistance possibility, the COVID-19 Treatment Guidelines Panel (the Panel) continues to recommend bebtelovimab for the treatment of COVID-19 only when ritonavir-boosted nirmatrelvir or remdesivir cannot be used in adults at high risk of severe, progressing COVID-19. The Panel also continues its recommendation for the use of COVID-19 mAbs tixagevimab plus cilgavimab as preexposure prophylaxis for patients.

The Panel will continue to monitor the prevalence of subvariants that may be resistant to COVID-19 mAbs. Currently, the prevalence is at a low or moderate level.


—Jessica Ganga



  1. Coronavirus (COVID-19) update: FDA authorizes Moderna and Pfizer-BioNTech bivalent COVID-19 vaccines for use as a booster dose in younger age groups. News Release. US Food and Drug Administration; October 12, 2022. Accessed on October 31, 2022.
  2. US Food and Drug Administration. COVID-19 bivalent vaccine boosters. US Food and Drug Administration. October 12, 2022. Accessed on October 31, 2022.,caused%20by%20the%20omicron%20variant.
  3. FDA releases important information about risk of COVID-19 due to certain variants not neutralized by Evusheld. News Release. US Food and Drug Administration; October 3, 2022. Accessed on October 31, 2022.
  4. Yeo YH, Wang M, He X, et al. Excess risk for acute myocardial infarction mortality during the COVID-19 pandemic. J Med Virol. Published on September 29, 2022. doi:10.1002/jmv28187.
  5. The COVID-19 treatment guidelines panel’s statement on omicron subvariants and anti-SARS-CoV-2 monoclonal antibodies. News Release. The National Institutes of Health; October 19, 2022. Accessed on October 31, 2022.