FDA approves updated Covid-19 vaccines to combat new variants


The US Food and Drug Administration (FDA) has approved and authorized for emergency use updated Covid-19 vaccines from Moderna and Pfizer/BioNTech that are designed to better protect against the currently circulating variants of the coronavirus, especially the omicron variant XBB.1.5.

Updated vaccines target omicron variant XBB.1.5

The updated vaccines are similar to the previously approved formulas, but they have been modified to include a single component that corresponds to the omicron variant XBB.1.5, which was first detected in South Africa in August 2023 and has since spread to more than 100 countries. The omicron variant XBB.1.5 is believed to be more transmissible and more resistant to the existing vaccines than the original strain of the virus.

The FDA said that the updated vaccines are expected to provide good protection against Covid-19 from the currently circulating variants, based on the totality of the evidence and input from the agency’s expert advisors. The FDA also said that barring the emergence of a markedly more virulent variant, it anticipates that the composition of Covid-19 vaccines may need to be updated annually, as is done for the seasonal influenza vaccine.

Eligibility and availability of updated vaccines

The updated vaccines are approved for people 12 years of age and older, and are authorized under emergency use for 6 months through 11 years old. The FDA said that individuals 5 years of age and older, regardless of previous vaccination, are eligible to receive a single dose of an updated mRNA Covid-19 vaccine at least 2 months since the last dose of any Covid-19 vaccine.

FDA approves updated Covid-19

Individuals 6 months through 4 years of age who have previously been vaccinated against Covid-19 are eligible to receive one or two doses of an updated mRNA Covid-19 vaccine, depending on the previous Covid-19 vaccine received3. Unvaccinated individuals 6 months through 4 years of age are eligible to receive three doses of the updated authorized Pfizer-BioNTech Covid-19 Vaccine or two doses of the updated authorized Moderna Covid-19 Vaccine.

The FDA said that it is confident in the safety and effectiveness of these updated vaccines and that the benefits outweigh their risks for individuals 6 months of age and older. Individuals who receive an updated mRNA Covid-19 vaccine may experience similar side effects as those reported by individuals who previously received mRNA Covid-19 vaccines, such as pain, redness, swelling at the injection site, fatigue, headache, muscle pain, chills, fever, and nausea.

The manufacturers have publicly announced that the updated vaccines would be ready this fall, and the FDA expects that they will be available in the near future. The US Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices will meet tomorrow (Sept. 12) to discuss clinical recommendations on who should receive an updated vaccine, as well as further considerations for specific populations such as immunocompromised and older individuals.

Vaccination remains critical to public health

The approval and authorization of the updated vaccines come amid an increase in Covid-19 hospitalizations and deaths in the US, which have surpassed 100,000 and 2,000 per day respectively in recent weeks. The delta variant remains the dominant strain in the country, accounting for more than 99% of sequenced cases. However, the omicron variant XBB.1.5 has also been detected in several states, raising concern about its potential impact on the pandemic.

“Vaccination remains critical to public health and continued protection against serious consequences of COVID-19, including hospitalization and death,” said Peter Marks, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research. “We encourage all eligible individuals who have not yet been vaccinated or who are due for a booster dose to get vaccinated as soon as possible.”


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