Vaccination during pregnancy reduces childhood infections; vaccines only modestly reduce long-term COVID risk

Vaccination during pregnancy reduces childhood infections;  vaccines only modestly reduce long-term COVID risk

June 2 (Reuters) – The following is a summary of some recent studies on COVID-19. They include research that deserves further study to corroborate the findings and that has not yet been certified by peer review.

Vaccines in pregnancy reduce infants’ risk of COVID-19

Vaccination against COVID-19 during pregnancy appears to reduce the risk of coronavirus infection in newborns, according to a study conducted in Norway.

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Norwegian researchers followed 9,739 babies whose mothers received a second or third dose of a COVID-19 vaccine from Pfizer (PFE.N)/BioNTech (22UAy.DE) or Moderna (MRNA.O) during pregnancy, and 11,904 babies whose mothers were not vaccinated before or during pregnancy. Overall, COVID infections were rare in babies. But the risk of a positive COVID-19 PCR test in the first four months of life was 71% lower during the Delta era and 33% lower when Omicron was dominant for babies whose mothers were vaccinated during pregnancy compared to infants born to unvaccinated mothers, researchers reported Wednesday in JAMA internal medicine.

“There might still be a protective effect of antibodies beyond the first four months, but there are probably individual differences,” said Dr Ellen Oen Carlsen of the Norwegian Institute of Public Health. Babies get another type of antibody from breast milk, she noted, and the findings could be partly due to antibodies acquired while breastfeeding, or because vaccinated mothers are less likely to contract COVID. -19 and infect their babies.

Infants of women who received a booster shot during pregnancy had an even lower risk of COVID-19 than those of women who received only the initial two-shot regimen. “This could imply that women who were vaccinated before pregnancy with two doses should consider receiving a booster dose during the later parts of pregnancy,” Carlsen said.

Vaccines only modestly reduce long-term COVID risk

The risk of developing long COVID after infection with the coronavirus is lower for vaccinated people than for the unvaccinated, but not by much, according to a large study by the US Department of Veterans Affairs.

Researchers compared the results of nearly 34,000 people who had breakthrough SARS-CoV-2 infections after receiving vaccines from Johnson & Johnson (JNJ.N), Pfizer (PFE.N)/BioNTech (22UAy.DE) or Moderna (MRNA.O), and more than 113,000 unvaccinated people who have been infected. The study, conducted when the Delta variant was predominant and published in natural medicine, found that vaccination reduced the likelihood of long COVID after infection by only about 15%. There was no difference in the type or severity of long COVID symptoms between vaccinated and unvaccinated patients.

The researchers also compared hospitalized patients with breakthrough COVID to hospitalized patients with seasonal flu. “SARS-CoV-2 breakthrough was associated with a higher risk of death than influenza,” study leader Dr. Ziyad Al-Aly, VA St. Louis Health Care System, said in a tweet. . “The results indicate that relying on vaccines as the sole line of defense is not an optimal strategy,” he told Reuters.

Impact of coronavirus variants depends on location

A new approach to visualizing viral evolution could help predict if and when a new coronavirus variant is likely to outperform currently dominant versions, researchers say.

“Mutations alone cannot answer the question” of whether one variant will prevail, said Venky Soundararajan of Massachusetts-based data analytics firm nference. To estimate a variant’s potential impact, the “distinctiveness” of its mutated gene sequences from previously circulating variants must be considered in the context of each geographic area, Soundararajan said. Genetic changes that confer distinctiveness in one geographic region might not do so in another region, depending on the variants that have circulated there, his team said in a report published Thursday on medRxiv before peer review. Studying a database of nearly 8 million SARS-CoV-2 samples from around the world, the researchers tracked and compared the evolutionary genetic sequences of the variants to which populations in different regions have been exposed – which the this is called the herd show. The distinctiveness of a lineage in a given country during a specific time window was significantly related to its change in prevalence in that country over the following eight weeks, they found.

The researchers are working with the US National Institutes of Health on a system that will alert public health officials when new variants arise to which communities are likely to be vulnerable. These are the variants that show the most differences both from the original version of the virus on which current COVID-19 vaccines are based and from the variants against which local residents have acquired some immunity through exposure. of the herd.

Click for a Reuters Chart on vaccines in development.

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Reporting by Nancy Lapid; Editing by Bill Berkrot

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