COVID-19 Roundup: Booster Eligibility, Pre-Exposure Prevention, Vaccination and Omicron Variant, Pediatric Vaccination Rates

FDA Authorizes COVID-19 Pre-Exposure Prevention¹

The US Food and Drug Administration (FDA) has issued an emergency use authorization for the use of monoclonal antibodies for the pre-exposure prophylaxis of COVID-19 in certain individuals. These new monoclonal antibodies may provide protection for up to 6 months.

Included in the eligible populations are individuals aged 12 years or older who weigh at least 40 kg. Individuals must have moderately to severely compromised immune systems or be taking immunosuppressive medications or have a history of severe adverse reactions to a COVID-19 vaccine and/or a component of those vaccines. All eligible individuals cannot be currently infected with COVID-19 and must not have been recently exposed to an individual currently infected with COVID-19. These monoclonal antibodies are not a replacement for vaccination.

The monoclonal antibodies, evusheld, is produced by AstraZeneca. Evusheld is administered in 2 consecutive injections of tixagevimab and cilgavimab. Possible adverse events include hypersensitivity reactions, bleeding at the injection site, headache, fatigue, and cough.

Vaccine Neutralizes Omicron Variant²

Three doses of the Pfizer-BioNTech COVID-19 may neutralize the omicron variant, according to the preliminary results of the manufacturer’s laboratory study.

A third dose provides antibody levels similar to those of 2 doses against wild-type and other variants. Compared with 2 doses, a third dose produced approximately 25 times more neutralizing antibody titers. However, 2 doses may still provide protection against severe disease.

To measure vaccine effectiveness against omicron, the researchers examined a panel of human immune sera. Blood samples were obtained from individuals who had received 2 or 3 doses of the Pfizer vaccine, 3 weeks after the second dose or a month after the third dose. After 3 doses, the geometric mean titer of neutralizing antibodies was 154 for the omicron variant, 398 for the Delta variant, and 155 for the original strain.

Pfizer-BioNTech expects an omicron variant-specific vaccine to be produced by March 2022.

Pediatric Vaccination³

Vaccination in children aged 5 to 11 years has slowed significantly after an initial surge following the Centers for Disease Control and Prevention’s recommendation for vaccinating this population, according to the results of a new analysis.  

Approximately 16.7% of these children have received at least 1 dose of a COVID-19 vaccine, and 4.3% are fully vaccinated.

However, vaccination in this patient population varies significantly acorss different regions of the United States. States in the Northeast such as Vermont and Massachusetts had higher vaccination rates, while states in the South such as Louisiana and Alabama had lower vaccination rates. The state with the highest vaccination rate in this patient population is Vermont, at 45.6%. The state with the lowest is West Virginia, at 3.6%.

Vaccination rates by state for children is often similar to vaccination rates for adults. A total of 34 states had vaccination rates for children aged 5 to 11 years that fell within 10 points of coverage for adults.

“This drop-off began before the Thanksgiving holiday and has continued since, suggesting that eager parents and caregivers, who make vaccination decisions for children, have already come forward,” the researchers concluded. “Indeed, our polling has found that two-thirds of parents say they will wait and see or won’t get their child vaccinated against COVID-19 at all, and this next phase of our vaccination effort will likely be much harder.”

FDA Expands Booster Eligibility⁴

Individuals aged 16 and 17 years old are now eligible for a booster dose of the Pfizer-BioNTech COVID-19 vaccine, following an amendment to the US FDA's emergency use authorization. 

Individuals must have completed the vaccine series at least 6 months prior to receiving the booster dose. 

This approval is based on an analysis of immune response data that was previously used in the authorization of a booster dose in individuals aged 18 years or older. Additional real-world data following prior authorization enabled the FDA to assess the risks of myocarditis and pericarditis with the vaccine benefits. 

"The Pfizer-BioNTech COVID-19 vaccine has been available to individuals 16 years of age and older for nearly a year, and its benefits have been shown to clearly outweigh potential risks," said the direct of the FDA's Center for Biologics Evaluation and Research Peter Marks, MD, PhD. "Since we first authorized the vaccine, new evidence indicates that vaccine effectiveness against COVID-19 is waning after the second dose of the vaccine for all adults and for those in the 16- and 17-year-old age group. A single booster dose of the vaccine for those vaccinated at least 6 months prior will help provide continued protection against COVID-19 in this and older age groups." 

—Leigh Precopio