Centers for Disease Control and Prevention (CDC) Director Rochelle Walensky, MD, MPH, on June 24 endorsed the Advisory Committee on Immunization Practices’ recommendation to offer the Moderna COVID-19 vaccine to children and adolescents ages 6 to 17. The Food and Drug Administration (FDA) amended the vaccine’s emergency use authorization on June 17 to include this age group. The vaccine now is authorized for use in all individuals ages 6 months and older.
FDA Committee Deliberates Vaccine Composition
FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) meets June 28, from 8:30 am to 5 pm ET, to discuss whether and how the SARS-CoV-2 strain composition of COVID-19 vaccines should be modified as new virus variants emerge.
Omicron Variant Mutations
By late December 2021, the omicron variant of SARS-CoV-2 became the dominant virus variant in the United States. As of early May, an omicron sublineage virus, BA.2.12.1, became the dominant strain in the United States, and two additional sublineages, BA.4 and BA.5, are spreading rapidly.
The quick mutation of the omicron sublineages poses concerns about vaccine efficacy; the spike protein of the omicron virus has more than 30 mutations compared with the antigen used in currently available COVID-19 vaccines. Of those mutations, 15 are in the spike receptor binding domain, the primary target of neutralizing antibodies stimulated by infection and vaccination.
WHO Advisory Group Recommendations
The World Health Organization (WHO) Technical Advisory Group on COVID-19 Vaccine Composition has urged COVID-19 vaccine manufacturers to collect and share data on the performance of current COVID-19 vaccines that use prototype virus strains from early in the pandemic, as well as variant-specific virus strains.
In interim guidance issued June 17, the WHO advisory group noted that currently available vaccines provide a high level of protection against severe disease outcomes for all virus variants, including omicron, as long as the primary vaccination series is supplemented with a booster vaccine dose. The advisory group noted that including an omicron component in a booster vaccine dose for those who previously received a COVID-19 vaccination primary series might achieve broader immunity against recent circulating virus variants.
Notably, the advisory group did not recommend the use of an omicron-specific monovalent vaccine, which would contain antigens from solely the omicron variant, citing uncertainty about whether this vaccine would offer the same amount of protection against severe disease that existing vaccines have demonstrated.
VRBPAC will consider data evaluating omicron-specific vaccines from both Moderna and Pfizer.
In a study of Moderna’s vaccine candidate, previously uninfected adults received a second booster of either mRNA-1273, Moderna’s authorized vaccine which contains 50 micrograms (µg) of the original mRNA-encoding S protein, or its candidate bivalent vaccine mRNA-1273.214, which contains 25 µg each of the original S protein and the omicron-specific S protein.
Compared with the original booster, the bivalent mRNA-1273.214 booster generated a statistically superior neutralizing antibody response against the omicron variant. This study suggests that including an omicron component in the second booster vaccination improves the neutralizing antibody response against the omicron variant without compromising the response against the ancestral virus strain.
In a study of Pfizer’s vaccine candidate, adults ages 18 to 55, with or without evidence of prior infection, received a second booster of either BNT162b2, Pfizer’s authorized vaccine that contains 30 µg of the original mRNA vaccine, or its candidate omicron-specific vaccine BNT162b2 OMI, which contains 30 µg of omicron mRNA. Compared with the original booster, the BNT162b2 OMI generated a superior neutralizing antibody response to the omicron variant.
FDA Committee to Review Pulse Oximeter Accuracy
FDA announced June 21 that its Medical Devices Advisory Committee will meet later this year to evaluate the accuracy and performance of pulse oximeters, which often are used to measure the amount of oxygen in the blood of COVID-19 patients. Recognizing concerns that pulse oximeters might be less accurate in people with darker skin pigmentations, the committee will develop recommendations for patients and health care providers, determine the amount and type of data that manufacturers should provide to assess accuracy, and consider future regulatory action.
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Contact Senior Director of Policy Erin O’Malley at firstname.lastname@example.org or 202.585.0127 with questions.