By Kristen V Brown

Will the vaccines be updated for delta?

In this week’s edition of the Covid Q&A, we look at the question of whether vaccines will be reformulated to protect against the delta variant. In hopes of making this very confusing time just a little less so, each week Bloomberg Prognosis is picking one question sent in by readers and putting it to experts in the field. This week’s question comes to us from Scott in Palm Beach Gardens, Florida. Scott asks:

I remember hearing the CEO of Moderna suggest that they could easily update the vaccine to take into consideration new variants. Will shots be updated for the delta variant?

Whether we all might need another round of vaccines is the question of the hour. It’s become clear that, either because of waning vaccine efficacy, the transmissibility of delta, a return to pre-pandemic social mixing or some combination of all three, immunized people seem more vulnerable to infection than previously thought.

On Aug. 12, U.S. regulators announced that immunocompromised individuals who received a two-dose regimen of Moderna or Pfizer vaccines should receive a third shot. Then last week, the Biden administration said adults who received the same two-dose course would be eligible for a booster eight months after their second shot, beginning Sept. 20.

It’s worth noting, however, that within the scientific community, the question of whether we might need boosters at all is still a subject of hot debate. Many scientists say the data still doesn’t suggest boosters are necessary at all, and have criticized the administration for acting rashly.

The issue is two-fold. First, there are several other variables that could be leading to a rise in cases among vaccinated people — the effectiveness of the shots isn’t the only answer. And even if efficacy is waning, it still appears that the shots largely protect against severe illness, which is the primary goal of vaccination.

Now, on to Scott’s specific question about vaccines and delta. For an answer, we turn to Ramon Lorenzo Redondo, a molecular virologist at Northwestern University.

“Although according to several companies, updated versions of the vaccines are being studied, these updated vaccines might not be required yet,” he says. “Unless there is clear evidence of loss of protection, updating the vaccines every time a new variant takes over the population might not be the best strategy.”

Remember that several variables could be contributing to vaccine breakthrough cases, so we just don’t have sufficient evidence yet that delta is the cause.

“If we were to update the vaccine at every major shift of the viral population, we would enter in a never-ending process that would be inefficient and probably unattainable due to the logistics and testing needed to approve each vaccine iteration,” he says. “Only if the data ever shows a significant loss of vaccine efficacy that could imply a breach in the defense vaccination provides, vaccine updates will become a necessary step.”

The reason for the booster, he says, is that studies have indicated a third dose of vaccine further increases the antibody levels against the virus present in the body, making breakthrough infections less likely.

But perhaps more importantly, even as breakthrough infections appear to be increasing, it is clear that even in the face of delta, the existing vaccines are still extremely protective.

”The data indicates that despite the rise of delta, full vaccination is still effective at preventing hospitalization and death,” he says. “The virus has slightly changed its structure, but it seems that so far it has not been enough to trick the vaccine-elicited immune response.”

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