June 30 (Reuters) - The following is a summary of some recent studies on COVID-19. They include research that warrants further study to corroborate the findings and that has yet to be certified by peer review.

Pausing immunosuppression improves COVID-19 booster response

People taking a commonly-used drug for inflammatory conditions such as rheumatoid arthritis or psoriasis get weaker-than-average protection from COVID-19 vaccines, but stopping the drug for two weeks after a booster dose doubled patients' antibody response in a randomized trial.

UK researchers studied 254 adults receiving methotrexate for their conditions who were about to get their third dose of a vaccine from Pfizer/BioNTech, Moderna , or AstraZeneca. Participants were randomly assigned to interrupt methotrexate treatment for two-weeks after the booster, or to continue taking methotrexate as usual. Blood tests one and three months later showed antibody levels were more than twice as high among patients who paused methotrexate for two weeks as among patients who kept taking it. This was true regardless of methotrexate dose, type of inflammatory disease, type of vaccine, and whether or not patients had ever been infected with SARS-CoV-2. Patients' reports of disease flares were slightly more common in the interruption group, but there was no difference between the groups in seeking healthcare input for flares, and there was no impact on quality of life or general health, the researchers reported on Monday in The Lancet Respiratory Medicine https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(22)00186-2/fulltext.

"Further research is required to assess whether interruption in treatment with other similarly acting immunosuppressive drugs will also enhance vaccine-induced immunity," the researchers said.

First-trimester COVID-19 vaccine particularly beneficial

Pregnant women getting vaccinated against COVID-19 should consider the type and timing of vaccination, new research suggests.

The 158 pregnant women in the study received mRNA vaccines from Moderna or Pfizer/BioNTech or the adenovirus-based vaccine from Johnson & Johnson. As reported on Tuesday in Nature Communications https://www.nature.com/articles/s41467-022-31169-8, the Moderna shot provided subtle advantages over the Pfizer shot in antibody levels and function, and both RNA vaccines induced more potent antibodies than the J&J shot. Immune responses to the shots were stronger when administered in the first or third trimester compared to the second trimester, while the transfer of protective COVID-19 antibodies to the fetus through the placenta was most efficient following first and second trimester vaccination.

When unvaccinated women become pregnant, the U.S. Centers for Disease Control and Prevention advises vaccination as soon as possible to maximize the amount of time during which the mother and fetus are protected from COVID-19. The researchers say their findings show that first-trimester vaccination induces an immune response as good as or better than responses later in pregnancy, along with "high transfer efficiency" of antibodies to the fetus. Furthermore, "maternal and neonatal immunity may be further enhanced by boosting in the third trimester," the researchers said.

Click for a Reuters graphic https://tmsnrt.rs/3c7R3Bl on vaccines in development.

(Reporting by Nancy Lapid; Editing by Bill Berkrot)