A panel of independent vaccine experts from the Food and Drug Administration voted 19 to 2 on Tuesday to recommend new Covid-19 shots targeting the omicron variant this fall, as public health officials expect a new wave of infections.
The commission, for the first time, suggested that vaccine manufacturers change vaccines to target them with a different option. The FDA will likely accept the committee’s recommendation and allow the vaccine change. However, the commission made no recommendations as to which sub-variant of the omicron should be targeted for shots.
pfizer, Modern, Novax as well as Johnson and Johnson they all developed their vaccines against the original strain of Covid, which first appeared in Wuhan, China in 2019. But as the virus has evolved rapidly over the course of the pandemic, vaccines have become less effective at protecting against infections and mild illness, although they still usually protect against serious illness.
A healthcare worker prepares a Moderna COVID-19 vaccine syringe at a temporary vaccination site operated by SOMOS Community Care during the COVID-19 pandemic in Manhattan, New York, January 29, 2021.
Mike Segar | Reuters
The vaccines target the spike protein that the virus uses to enter human cells. However, the shots have trouble recognizing and attacking the spike the more it mutates from the original version of the virus. The omicron variant is the most impressive example, although it contains over 30 mutations. This is one of the central reasons why omicron caused such a massive wave of infections last winter, despite the fact that masses of people were fully vaccinated.
Omicron continues to mutate into more infectious sub-variants. Dr. Peter Marks, head of the FDA’s vaccine division, said the US will face a Covid outbreak this fall and winter as the virus evolves, vaccine immunity wanes and people spend more time indoors, where Covid can spread much more easily than outside.
“For this reason, we should seriously consider launching a support campaign this fall to protect us,” Marks told the committee. “The better the match of the vaccine to the circulating strain, we think this could translate into improved vaccine efficacy and possibly longer durability of protection.”
Justin Lessler, an epidemiologist at Chapel Hill University of North Carolina, said another 95,000 people could die from Covid in the US by March 2023. forecasts of a group of scientists who develop pandemic trajectory models. According to him, under the most pessimistic scenario, by March next year, 211,000 people could die from the virus. However, Lessler warned that there are many uncertainties in these forecasts.
According to data provided by the Centers for Disease Control and Prevention, three doses of current vaccines are only 19% effective in preventing omicron infection in adults aged 18 years and older 150 days or more after administration. This low protection against infection is likely because omicron has evolved into the more infectious sub-variants BA.2 and BA.2.12.1, said Centers for Disease Control and Prevention (CDC) official Dr. Ruth Link-Gelles said. The third dose was reported to be 55% effective in preventing hospitalization due to these sub-options in adults 120 days or more after vaccination.
The virus is evolving so fast that vaccine manufacturers are having a hard time keeping up. Pfizer and Moderna developed their omicron shots from the original version of the BA.1 variant. However, BA.1 no longer circulates in the US. In the spring, the more infectious omicron subvariant, BA.2, began to dominate. According to Marks, the BA.4 and BA.5 omicron sub-variants are now rapidly gaining popularity in the US and poised to become dominant.
Pfizer and Moderna presented data based on small studies of a few hundred people showing that their omicron shots significantly increased the immune response against omicron BA.1 compared to the original shots that targeted the strain of the virus that originated in China. However, the updated vaccines did not work as well against BA.4 and BA.5, although the immune response was still strong. There is no data available on the actual effectiveness of the updated vaccines, although the strength of the immune response is generally regarded as an indication of how well the vaccines will provide protection against disease.
But dr. Paul Offit, a member of the committee, said it was unclear whether the immune response data would lead to significant protection.
“I just think we need a higher standard of protection than what we’re given — I think that’s inconvenient,” Offit, an infectious disease expert at the Children’s Hospital of Philadelphia, said of the data presented at the meeting.
The FDA panel members seemed to agree that it would be better to target omicron BA.4 or BA.5. But this could create logistical problems for vaccine companies as they were focused on BA.1. The production process for another sub-variant would have taken about three months.
Panel member Dr. Mark Sawyer said the FDA risks falling further behind the evolution of the virus if it doesn’t act soon.
“Given this state of evolution, we would fall behind the top eight if we wait longer,” said Sawyer, professor of pediatrics at the University of California, San Diego.
Novavax presented data showing that a booster dose of its current vaccine, targeting the parent strain of the virus, elicited a strong immune response against omicron subvariants. Dr. James Hildreth, ad interim committee member, said he was most impressed by the Novavax data and urged the FDA to quickly approve the vaccine for use in the US. However, FDA spokesman Jerry Weir said the Novavax data has not been independently verified by the agency.
Panel member Dr. Cody Meisner said he was concerned that there was not enough safety data on how changing the composition of the vaccine could affect heart inflammation or myocarditis as a side effect. Current Pfizer and Moderna vaccinations are associated with an increased risk of myocarditis in adolescent boys.
“We need more research or research on what is related to vaccines and myocarditis,” Meisner said.
Marks said it was important to make a decision as soon as possible on whether to update vaccines so that manufacturers have time to produce shots by the fall. However, Congress has not allocated money to the US to purchase additional vaccines. The White House has warned that without additional US funding, vaccinations may need to be limited to people at higher risk, such as the elderly, in the fall.
Dr. Ashish Jha, who is coordinating the U.S. response to Covid, said other countries have already entered into talks with vaccine makers about the updated shots. The White House has provided $5 billion to fund talks with companies as the administration expects more money from Congress. The $5 billion the White House is using for vaccines was originally earmarked for Covid tests and protective equipment, meaning there is now less money for those other important tools to fight the pandemic.