Answers to questions about the updated Covid-19 vaccines

Updated Covid-19 vaccines from Pfizer/BioNTech and Moderna have rolled out to pharmacies. The Food and Drug Administration approved the mRNA vaccines for everyone 6 months and older. The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices voted 13-1 to recommend that everyone 6 months and older should get the shots, and the CDC endorsed that recommendation.

Lori Robertson and Catalina Jaramillo of, a service of the Annenberg Public Policy Center at the University of Pennsylvania. Robertson and Jaramillo compiled a list of common questions and answers about the vaccines, and here’s a condensed version of their report:

How are these updated shots different from the last one? All of the Pfizer/BioNTech and Moderna Covid-19 vaccines — the originals, the bivalent boosters and the latest updates — use the same mRNA technology to trigger an immune response to the spike protein of SARS-CoV-2, the virus that causes Covid-19. The spike protein is what the virus uses to enter cells.

The difference between the versions of the vaccines is in what type of spike protein they prompt the body to make. The mRNA in the 2023-2024 vaccines instructs cells to make the spike protein of omicron variant XBB.1.5. The variant became a concern at the end of last year, when the CDC projected it made up 40.5% of new CCovid-19 cases in the U.S., a figure that rose to nearly 90% by early March.

Who is eligible to get an updated vaccine? Everyone 6 months of age and older is eligible for these vaccines.The FDA said those age 5 and older can get a single dose of either mRNA vaccine if at least two months have passed since the prior Covid-19 vaccine dose. Unvaccinated people can also get a single dose. Children ages 6 months through 4 years who previously were vaccinated are eligible to get one or two doses, depending on which vaccines they have received and when. Children in this age group who haven’t been vaccinated against Covid-19 can get three doses of the latest Pfizer vaccine or two doses of Moderna’s. . . . Those who are immunocompromised can also receive additional doses.

What evidence supports the use of the updated vaccines? The FDA said it approved and authorized the latest formulas of the vaccines based on its evaluation of manufacturing data and data showing the immune response to these vaccines against prevalent variants is similar to that of previous versions of the vaccines against prior variants.. . . . The FDA is using a similar approach to the annual influenza vaccines, which are tweaked each year to combat the influenza strains expected for that season. Flu vaccines are approved each year without clinical studies because the changes, compared with prior vaccines, are small and because it wouldn’t be possible to test the vaccines each year in people before the flu season.

How effective are they? We don’t have vaccine effectiveness data for the updated vaccines specifically, but data on similar, previous vaccines show they were quite effective at preventing severe disease. And the research. . . .by Moderna and Pfizer/BioNTech shows the updated version increases neutralizing antibodies against the new and emerging variants.

How safe are they? Moderna’s clinical trial for the latest vaccine showed that the percentage of participants reporting mild side effects, such as pain, swelling, headache, fatigue and muscle aches, was similar to or, in many cases, lower than the reporting rates for the prior Covid-19 vaccines. But, the safety evaluation of this formula is based on hundreds of millions of doses of Covid-19 vaccines administered over the past few years.

Are the shots still free, and where can I get one? The vaccines are no longer provided by the federal government for free, but private insurance companies, Medicare and Medicaid, and some CDC programs will cover them.

For more detailed explanations and questions, read the full article here.

Previous Article
Next Article