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COVID-19: New Subvariant on Rise, Moderna Seeks Pediatric EUA

A new subvariant of SARS-CoV-2, the virus that causes COVID-19, is spreading in the United States. First identified in upstate New York, the BA.2.12.1 subvariant now constitutes 36.5 percent of genomic sequences identified nationally,

The new subvariant is 25 percent more transmissible than the BA.2 subvariant, the predominant variant in the United States, Centers for Disease Control and Prevention (CDC) Director Rochelle Walensky, MD, MPH, reported in an April 26 briefing. Research is underway to determine vaccine effectiveness against BA.2.12.1.

Study: Infection-Induced Antibodies Increased during Omicron-Predominant Period

A recent study published in CDC’s Morbidity and Mortality Weekly Report shows an increase in the seroprevalence of infection-induced SARS-CoV-2 antibodies in the U.S. population during the period when the omicron variant (B.1.1.529) was predominant in the United States.

From September to December 2021, overall seroprevalence increased by 0.9 to 1.9 percentage points per four-week period. From December 2021 to February 2022, seroprevalence increased from 33.5 percent to 57.7 percent. The largest increases were observed in children and adolescents younger than 17, nearly 75 percent of whom had infection-induced antibodies in February 2022. These findings illustrate a high infection rate for the omicron variant, especially among children.

Moderna Files for Pediatric Vaccine EUA

Moderna Inc. on April 28 filed a request to the Food and Drug Administration (FDA) for emergency use authorization (EUA) for its COVID-19 vaccine in children ages 6 months to younger than 6 years.

Children in this age group will receive two 25-microgram doses of Moderna’s mRNA-1273 vaccine, compared with the 100-microgram dose adults receive. Interim results from Moderna’s Phase 2/3 KidCOVE study showed a robust neutralizing antibody response, antibody titers that met the statistical criteria for similarity to the adults in the COVE study, and a positive safety profile. The EUA submission will be complete in early May.

FDA Schedules Tentative Vaccine Advisory Meetings

FDA has scheduled tentative virtual meetings of its Vaccine and Related Biological Products Advisory Committee (VRBPAC), in June, to discuss several EUA submissions underway.

On June 7, the committee plans to discuss an EUA request filed by Novavax Jan. 31 for its COVID-19 vaccine for individuals 18 and older. Unlike the Pfizer and Moderna vaccines, which use mRNA technology, and the Janssen vaccine, which uses viral vector technology, the Novavax vaccine is a protein sub-unit vaccine, which uses a portion of the SARS-CoV-2 virus’ harmless spike protein to stimulate an immune response. The vaccine is given in two doses, 21 days apart, and can be stored at refrigerator temperatures. The vaccine has received conditional authorization in other countries worldwide but has yet to receive FDA authorization.

Tentative meetings on June 8, 21, and 22 will focus on updates to the Moderna and Pfizer EUAs for their COVID-19 vaccines to include younger populations. Pfizer applied in February for EUA for the first two doses in a three-dose, three-microgram COVID-19 vaccine series for children 6 months to 4 years old but later asked the agency to delay review until data from all three doses was available.

On June 28, VRBPAC plans to deliberate whether the SARS-CoV-2 strain composition of COVID-19 vaccines should be modified, and, if so, which strain(s) should be selected for future COVID-19 booster doses in fall 2022.

FDA will confirm these meeting dates when EUA submissions are complete.

FDA Extends Expiration Dates for Select At-Home Tests

FDA updated its list of authorized at-home, over-the-counter COVID-19 tests to reflect new information about test expiration dates.

The expiration date listed on the box label for at-home COVID-19 tests is set at the end of the shelf life, which indicates how long the test should perform as expected after its manufacture date. This time period is determined through stability testing, which determines how long COVID-19 test performance remains stable. Since stability testing takes time, FDA generally authorizes at-home COVID-19 tests with a four- to six-month shelf life, based on initial study results, and may extend expiration dates when stability testing results are available.

Tests with extended expiration dates include:

  • Abbott Diagnostics Scarborough Inc.’s BinaxNOW COVID-19 Ag Card Home Test and BinaxNOW COVID-19 Antigen Self Test;
  • Access Bio Inc.’s CareStart COVID-19 Antigen Home Test;
  • ACON Laboratories Inc.’s Flowflex COVID-19 Antigen Home Test;
  • Detect Inc.’s Detect COVID-19 Test;
  • Health Labs Inc.’s iHealth COVID-19 Antigen Rapid Test; and
  • InBios International Inc.’s SCoV-2 Ag Detect Rapid Self-Test.

If the Expiration Date column in the FDA test list does not say the shelf life is extended, the expiration date on the box label remains effective.

JAMA Study: Home Antigen Test Sensitivity Varies During Infection Period

A new study published in the Journal of the American Medical Association shows that home antigen test sensitivity varies during the course of SARS-CoV-2 infection.

A cohort of 225 adults and children with SARS-CoV-2 infection confirmed by a reverse transcription–polymerase chain reaction (RT-PCR) test tested daily for 15 days with a QuickVue At-Home Over-the-Counter COVID-19 Test, in addition to receiving at least one nasopharyngeal swab for RT-PCR, viral culture, and sequencing.

Antigen test sensitivity was 50 percent during the infectious period, 64 percent compared with same-day RT-PCR, and 84 percent compared with same-day cultures. Antigen test sensitivity peaked four days after illness onset at 77 percent and improved with a second antigen test one to two days later, particularly early in the infection. This study suggest that symptomatic individuals with an initial negative home antigen test result should test again one to two days later because test sensitivity appears to peak several days after illness onset.

Visit the America’s Essential Hospitals coronavirus resource page for more information about the pandemic.

Contact Senior Director of Policy Erin O’Malley at or 202.585.0127 with questions.


About the Author

Emily Schweich is a communications manager at America's Essential Hospitals.

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