Second COVID-19 Booster Provides Worse Protection Than First: Study
Protection provided by a second COVID-19 vaccine booster A new study found that shielding was less effective than the initial booster and tends to become negative over time.
Researchers in France concluded that 64 percent protection against symptomatic infection was achieved seven to thirty days following an initial Pfizer/Moderna booster. This is a significant improvement over the protection provided by a primary series. This is known as relative effectiveness.
The relative booster effectiveness against symptomatic infection, however, quickly dropped—reaching 33 percent 90 to 120 days after injection and 8.8 percent 150 to 180 days after infection, the French researchers found.
After 120 days, the shielding was increased to 39 percent with a second booster. However, the difference between the first and second boosters became negative. The difference reached negative 32.6 per cent after 210 days.
“Although additional protection with the second booster dose was achieved, it decreased over time reaching levels below 10% at >90 days post vaccine administration,” Cynthia Tamandjou and the other researchers, all with France’s national public health agency, said in their study, which was published as a preprint by medRxiv.
The lower protection from a second dose may stem from immune imprinting, or repeatedly stimulating people’s immune systems with vaccines aimed at the Wuhan virus variant.
While that approach helped protect against that variant, it hasn’t been in circulation since 2020. Omicron, and its subvariants, gained dominance in late 2021. Vaccines, aside from boosters in fall 2022 have remained the same.
“Frequent exposure to the same antigen is to the detriment of new neutralizing responses against variant antigens,” According to the researchers, The researchers called for human clinical trials to assess the effects of immune imprinting.
Researchers arrived at their results by analysing COVID-19 testing that had been logged through government surveillance systems. The tests were conducted on anyone who reported COVID-19-like symptoms. They also included people who tested positive for the disease and those who tested negative. Participants were 60 years or older, who had been tested between March 21st, 2022 and October 20th, 2022. If a booster was given at least seven days prior to the test, people were considered vaccinated. Researchers compiled 456,657 cases of vaccines and 476.834 controls.
There were possible confounding variables that could have an unmeasured effect on the results. This could include factors such as having been vaccinated. These factors could potentially influence the decision to get tested.
The paper was finished “as part of routine work at Public Health France,” The authors stated this in the section on funding disclosures. They didn’t report any other funding.
Research has shown that two-dose Primary Series vaccines from Moderna and Pfizer work much worse against Omicron, its subvariants, and provide protection against infection. nearing zero You can even get it! turning negative After a time. While protection against severe illness is higher than that offered by earlier strains, it is still lower than the former.
Booster dose protection also wanes rapidlyResearchers have discovered that. A recent study indicated The second booster is not as effective as the first.
Some other recent papers
A Dutch study on vaccine effectiveness found that the effectiveness for a primary series against infection in the Delta era was 47 per cent. However, this dropped to negative 36% when Omicron came out in late 2021. A booster could provide protection of 30 percent.
The researchers, with the National Institute for Public Health and the Environment, drew from surveys that were given to people who tested positive for COVID-19 who are participating in a five-year study on vaccine effectiveness.
“During the Omicron period no direct protection against infection was found,” According to the researchers.
They said they were unable to estimate the protection from a second booster because most people who weren’t vaccinated were under 60 and most people who received another booster were over 60, “resulting in a faulty comparison.”
They also calculated the effectiveness against transmission or infectiousness. The index cases without a primary sequence were effective at 45%, and index cases with a second booster at 64%. An index case was defined as someone who had tested positive for the disease in their household first. Persons with a history of infection were exempted.
Factoring in the time between vaccinations, the effectiveness of vaccines against infection was highest within the first three to six months. It dropped to 32 percent for primary series vaccines and to 58 percent for booster vaccines after three months.
The study period lasted from July 23rd 2021 to August 7th 2022.
The paper was published The preprint server medRxiv. Some infections could have come from other sources than the index case, which was a limitation.
A third paper, also from Dutch researchers and released ahead of peer review, estimated that people with a combination of vaccination and natural immunity had better protection against infection, but that additional vaccine doses didn’t increase shielding.
“This indicates that among populations with high levels of immunity, additional vaccine doses have the potential to reduce risk of any infection only temporarily,” The researchers drew on the same five-year research.
Study on the Coronavirus Vaccination, or VASCOThe national government finances the.
Pfizer and Moderna didn’t respond to requests for comment on the papers.
Zachary Stieber works as a senior reporter with The Epoch Times, Maryland. He reports on U.S. and global news.
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