While the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) recommend a bivalent booster for anyone over the age of 6 months, some physicians disagree.
This includes clinicians who discourage all COVID-19 vaccinations, and also those who endorse the primary shots but have reservations about boosting.
Dr. Paul Offit, an FDA committee adviser, on Jan. 11 discouraged bivalent boosters for young and healthy people in a commentary in the New England Journal of Medicine.
Offit, however, as a pediatrician, has voted to approve primary series vaccines for all age groups in previous advisory meetings.
“The landscape is different now" in January 2023 than it was in January 2022 or 2021, said pediatric disease specialist Dr. Cody Meissner, another FDA advisory committee member and professor of pediatrics at Dartmouth’s Geisel School of Medicine. “The equation changes as time goes by.”
The severity of COVID-19 is now receding into a background seasonal virus. The circulating disease is less virulent compared to the virus of the first outbreaks in the U.S. three years ago. Changes to the virus have likely made the current Omicron variant and its subvariants less apt to cause COVID-19 pneumonia, and most people now have a degree of immunity to the virus.
Chasing Variants Is Like a 'Hamster on Wheel'A major topic of contention is the public health agencies' approach to boosting people out of the pandemic by changing the vaccine content as the circulating variant changes.
However, physicians now argue that it is practically infeasible to continuously boost people.
In August 2022, the FDA authorized bivalent mRNA boosters with the hopes that the added Omicron mRNA components would better protect people.
However, reality showed that people could never get "up to date" on their immunity via vaccination, as once the boosters were rolled out, the variant the booster was based on would likely be no longer relevant.
Such was the case with the bivalent boosters. When the FDA committee advisors voted in June 2022 to approve bivalent vaccines that contained Omicron components, the data that they were presented with were from clinical studies that tested bivalent boosters that contained the Omicron BA.1 variant.
But by then the BA.4 variant was largely irrelevant and the BA.5 variant was also on the decline.
"The message seems to be that we need to vaccinate everybody, again and again, regardless of health status," Meissner said, but it's like "a hamster on a wheel."
"We shouldn't be making vaccines, every three or four months as a new variant circulates," said Meissner, arguing that the virus is likely to continue to mutate indefinitely and there may be downsides from frequent boosting.
Shifting Stance on Boosters for Younger PeopleDr. Prakash Nagarkatti, professor of pathology, microbiology, and immunology from the University of South Carolina, told The Epoch Times that the current booster strategy should be reconsidered, given that most younger people would have some form of immunity against COVID-19, and are at a lower risk of severe COVID-19, to begin with.
The point of boosting is to encourage immunity against the SARS-CoV-2 virus.
Dr. William Schaffner, professor of epidemiology and a non-voting member of the CDC's advisory committee said that the role of boosters in COVID-19 is to prevent severe disease that requires hospitalization and to prevent death—pointing to the CDC's own data showing lower hospitalization rates in vaccinated people.
However, other data on boosters' clinical efficacy has been contradictory.
These findings are all arguments of correlation, but physicians and immunologists are concerned that the repeated inoculations with the boosters may train the body to always muster the same immune response when encountering other strains of the virus, also known as immune imprinting.
This would mean that infections from newer variants like Omicron, may not be effectively cleared or may completely evade the immune response, both of which have already been reported with Omicron variants.
People who had a previous infection or vaccination with the adenovirus COVID-19 vaccine had zero or low IgG4 antibody responses, respectively.
As with all medical interventions, there is an evaluation of benefits and risks. While data on boosters give low to negligible benefits, there are clear risks.
Younger people, especially males, are the most at risk of developing myocarditis and pericarditis from vaccination and boosting.
Though most of the published studies show a significant myocarditis uptick after the second primary dose, it is possible that the risk of myocarditis persists or even elevates if the person takes one or more boosters.
"At this time, I would be hesitant to make too strong a recommendation for younger individuals, particularly college-age students to get frequent, multiple doses of these vaccines because the risk of undesirable side effects is not understood," Meissner said.
Nevertheless, studies have been limited and contradictory, with data from the CDC showing that myocarditis is reported less after the second primary shot.
Annual Boosters Possibly to ComeDocuments (pdf) for the upcoming Vaccines and Related Biological Products Advisory Committee (VRBPAC) meeting on Jan. 26 reveal that the FDA is considering changing boosters to be more like an annual flu shot.
For very young children, the elderly, and people with compromised immunity, there would be two-dose vaccines.
However, unlike influenza, predicting prevailing annual COVID-19 variants is quite challenging, and Meissner speculated that it is unlikely that the vaccine development model for influenza can be applied to COVID-19.
Currently, influenza variants are tracked by the World Health Organization (WHO) through its Global Influenza Surveillance and Response System which has more than 120 participating laboratories and collaboration centers around the world.
The WHO would then make recommendations on the prevailing variants for the Northern and Southern Hemispheres separately. The Southern Hemisphere experienced winter and its flu outbreak earlier. U.S. vaccine developers can use the recommendations for both hemispheres as a reference.
Besides, the changes the flu virus may take on between each variant are more predictable than the COVID-19 virus.
Influenza vaccinations are made to target the viruses' hemagglutinin (H) and neuraminidase (N) proteins on their outer surfaces since these proteins help the virus enter and leave cells. The changes of H and N proteins in influenza viruses would generally fall within a known range of potential mutations, making the virus easier to predict.
Most of the annual influenza pandemics are caused by influenza A and B viruses. Influenza A viruses, for example, have 18 and 11 different H and N protein types, and the dominant influenza A variant can be any combination of the H and N proteins.
The infamous Spanish flu was a combination of H1N1, meaning a combination of type 1 H and N proteins, and the type that commonly infects pigs is H3N2. Between subtypes there are also further changes classified as "clades," but regardless, the 18 and 11 different H and N subtypes would give researchers a good range and direction in vaccine development.
Influenza B also has its own lineage combinations.
However, as researchers have yet to establish a range for COVID-19 mutations, this would make variant predictions and vaccine development a lot more challenging.
"For SARS-CoV-2, we have no idea what mutations will occur," Meissner said, "It's a different virus."
While Meissner and Nagarkatti welcomed the discussion of a single annual booster, other physicians expressed concern that the VRBPAC committee would not be evaluating safety data on subclinical myocarditis risks during the meeting.
"It is impossible, in my view, to make a risk/benefit decision about annually boosting young people for covid without knowing if subclinical myocarditis is an issue, and without understanding the rate and long-term outcomes of myocarditis from boosters," tweeted Dr. Walid Gellad, professor of medicine from University of Pittsburgh, "Committee needs to discuss."
Prasad added that the VRBPAC meetings currently show no signs of raising important points including the possibility of having randomized clinical trials being done on annual boosters to ensure that it actually reduces severe disease and that even with annual boosters, the vaccines may still be chasing the last variant.