TFDA and CDC approved updated bivalent COVID-19 Vaccines last week. The mRNA vaccine technology platform has always been the promise that we can update it quickly. We may finally have an advantage over SARS-COV-2 because the updated vaccine recipe matches the current dominant BA.5 strain (and the slow-growing BA.4.6 strain) without another more transmissible variant of concern yet on the horizon.
However, we are concerned that the CDC may happen Once again missing the boat with his recommendations on timing Because that’s when most American adults should receive this drug. After the Advisory Committee on Immunization Practices (ACIP) meeting on September 1the CDC states that adults who have completed their primary vaccination series are eligible for the updated booster if they are at least two months since their previous vaccination. Advise them who have recently had an infection Wait 3 months before getting a payment.
However, such a short interval is not optimal if we are aiming for strong fall/winter protection and it can also be counterproductive. The CDC should recommend a 6-month interval between a previous booster dose or infection and a new updated vaccine for healthy adults for two main reasons: updated immunological studies and recognition that millions of Americans have had post-vaccination infections with omicron variants this year and therefore have strong protection against the current against Re-infection with BA.5.
we previously Called on the CDC To extend the recommended period between initial doses of two mRNA vaccines to 8 weeks primarily in Basis for immunological studies Showing a higher antibody response, amplified T cells, and enriched memory B cells with a longer time between doses.
Recent research studies During the Omicron variant era continued to show the benefit of an extended interval between doses in terms of increasing both neutralizing antibodies and memory B cells. Provides booster Antibody protection for at least 6 months According to a recent study. Another study showed that Antibody levels stabilized 6-9 months After vaccination for study participants, whether or not they had previous infections.
Memory B cells were more robust after vaccination – indicative of persistence of the reaction against all variants including Omicron for at least 9-10 months after the first two-dose series. With an additional positive response to a third booster dose. that Additional Study showed that memory B cells continue to mature for approximately 6 months, after vaccination or infection. B-cell immunity – as well T cell immunity COVID- VaccinesProvide protection against severe disease It did not lead to high levels of hospitalization as BA.5 became dominant this summer.
One of the goals of Omicron’s vaccines is to increase antibodies and prevent mild infections. Thus, a plateau of antibody level at the 6-month mark indicates an ideal time to boost with a BA. Increasing fold greater after reinforcement. In other words, high levels of circulating antibodies from a short-lived enhancer may limit the additional protection of another enhancer. else A recent study by the National Institutes of Health He showed the same concern after a recent injury, but more drastically: giving a booster dose two months after the last injury actually nullified potent B-cell responses.
Millions are infected with Omicron
a A recent study in JAMA showed that 56% of subjects with the Omicron variant were unaware of the infection. And the actual number of daily infections last summer far exceeds the official schedule given the volume of unreported at-home rapid antigen testing. In addition, millions of Americans have received their third and fourth vaccine doses in the past few months.
The utility of this degree of population immunity can be extrapolated from a A recent study from Portugal Which shows, in contrast to previous concerns about BA.5 re-infection, that prior BA.1/2 infection provides 75.3% protection against BA.5 re-infection. This was consistent with a file Qatar Study 79.7% shows protection against re-infection.
All of this data means that there is a significant amount of active population-level immunity to COVID-19 in the United States that protects against severe disease. Our reinforcement strategy should recognize this current immunity and seek to build on it in a way that extends the protection of this shot throughout the winter. Repeating the short-term booster or booster too soon after infection after vaccination reduces the neutralizing antibody response and impedes the expansion of memory B cells.
After significant input from experts, the CDC formally updated its guidance in February 2022 to recommend an extended dose interval for the primary vaccine series, but it has fallen significantly behind their counterparts in Canada, Europe and India to adopt this 8-week interval. Moreover, the vaccination period was not extended Very widely advertised. The CDC now has an opportunity to take these immunomodulatory principles of the updated Omicron Booster and make them work even better.
The Canadian National Advisory Committee on Immunization, already ahead of the curve, OFFICIALLY RECOMMENDED In the past week, that the updated bivalent vaccine be administered in a 6-month period after a previous vaccination or infection.
In a recent survey By the CDC, 72% of those surveyed “Sure” or “likely” to get an updated booster. Paying attention to the booster update is important because Only half qualified Americans got their first recommended booster dose and only 34% of those over 50 got a second booster dose. This is why it is so important that we get recommendations on the appropriate timing for this updated version of Omicron Booster, the first update in mRNA vaccines since its launch in January 2021.
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