Will the COVID-19 Vaccine Series Be Redesigned?

COVID vaccine illustration.

Namthip Muanthongthae / Getty Images

  • This week, an FDA panel discussed future pandemic safety measures and the potential for a new vaccine series
  • Experts stressed that the current vaccines continue to protect against severe disease and death, but that a new series could be important in targeting specific variants or reducing virus transmission.
  • More data COVID-19 variants, the virus’s seasonality, and global trends are needed to guide decisions.

A Food and Drug Administration (FDA) panel met on Wednesday to discuss the future of COVID-19 vaccinations, including the potential need for a variant-specific vaccine.

While the panel did not conclude whether a variant-specific vaccine was necessary, many experts stressed the importance of continued surveillance and ongoing meetings to prepare for such a need in the fall.

Some experts said the Omicron variant intensifies the need for changes to the primary vaccine series, as the variant has been able to evade vaccine immunity better than its predecessors, like Delta.

Pfizer and Moderna previously announced plans to develop an Omicron-specific vaccine, with Pfizer claiming its shot could be ready within 100 days. The manufacturers later announced that its timeline was delayed due to time lags in gathering data, Reuters reported. Pfizer has also previously tested other variant-specific vaccines targeted toward the Delta and Beta variants that were not found to be needed. To date, neither company has released an Omicron-specific vaccine.

Assessing the Need to Change Primary Vaccine Series

Adjusting the current COVID-19 vaccine series could be necessary to optimize the shot’s performance against emerging variants of concern, according to Kanta Subbarao, MD, MPH, who represents the World Health Organization’s Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC).

TAG-CO-VAC reviews evidence on COVID-19 and analyzes how variants may impact vaccine performance to help guide decisions for potential vaccine alterations. Currently, guidance could go in one of three directions, Subbarao said.

Considerations for an altered vaccine include:

  • Monovalent vaccine: A vaccine that elicits an immune response on one dominant variant, such as an Omicron-specific vaccine. This could most likely be a short term solution.
  • Multivalent vaccine: A vaccine that elicits an immune response on multiple variants. This could most likely be a mid-length solution.
  • Pan SARS-CoV-2 vaccine: A vaccine that elicits an immune response on, hopefully, all variants. This could be a longer term solution.

Gathering more data on circulating and emerging variants may be necessary for these ideas to come to fruition, Subbarao said.

But some panelists expressed doubts that a new vaccine series could be created.

“The challenges and unknowns outweigh our current ability to accurately predict a new cycle for a selection of new strains for a COVID-19 vaccine,” Michael Nelson, MD, PhD, chief of the division of asthma, allergy, and clinical immunology at the University of Virginia School of Medicine said at the meeting.

The Flu Shot as a Blueprint for COVID-19 Vaccine

To some extent, the ever-changing influenza vaccine presents a blueprint for how to change the COVID-19 vaccine. Still, the recipe cannot be replicated exactly, Subbarao said.

With influenza, a wealth of information on the flu’s genetic sequencing and antigenic characteristics—which typically come from three to 5,000 viruses—often influence vaccine alterations, she added.

For example, scientists can compare data to reference flu strains from the previous year and ones that are currently circulating. If a new flu variant appears to be antigenically distinct, occurring in more than one area or continent, and causing significant disease, that is a trigger for considering a modification of the vaccine, Subbarao said.

With COVID-19, much of this data has yet to be compiled. Among other information gaps, there is insufficient global surveillance on COVID-19 and its antigenic characteristics, Subbarao said. There is also limited information on specific variants due to how quickly they have mutated, as well as a lack of understanding of COVID-19’s seasonality, which is important for vaccine timing, she added.

“There are a lot of moving parts, but I think we will use what we know about influenza as the basis to try to put together some of the information that we need,” Subbarao said.

Although existing COVID-19 vaccines protect well against hospitalizations and death, they do not offer as much protection against infections, the panelists said.

“We do need to encourage the development of COVID-19 vaccine that will have an impact on prevention of infection and transmission, in addition to protecting against severe illness and death,” Subbarao said. “Until such vaccines are available, and as the virus continues to evolve, the composition of the current COVID-19 vaccines may need to be updated to ensure that they achieve protection.”

Can We Draw Conclusions From Limited Data?

Answering the question of if and when a new vaccine series should be available to the public will require more thought and more FDA meetings, said Peter Marks, MD, PhD, the director of the FDA’s Center for Biologics Evaluation and Research.

“We’re not going to have all the data that we’d like to have,” Marks said.

He added that he took to heart the totality of the discussion, restating the agency’s desire to provide a unified “strong man’s proposal” to advance vaccine protection.

What This Means For You

The FDA is contemplating potential changes to the COVID-19 vaccine series, such as developing a new vaccine to target emerging variants. Whether or not such a change is necessary or feasible has yet to be determined.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

1 Source
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  1. Chaguza C, Coppi A, Earnest R, et al. Rapid emergence of SARS-CoV-2 Omicron variant is associated with an infection advantage over Delta in vaccinated persons. medRxiv. Preprint posted online January 25, 2022. doi:10.1101/2022.01.22.22269660

By Claire Wolters
Claire Wolters is a staff reporter covering health news for Verywell. She is most passionate about stories that cover real issues and spark change.