News Scan for Jul 06, 2022

Fourth vaccine dose protects against Omicron in nursing home residentsA study in Ontario suggests that, compared with a third dose of mRNA COVID vaccine, a fourth dose improved protection against infection and severe outcomes among long-term care residents during the Omicron wave.

The study was published today in The BMJ.The study was conducted from Dec 30, 2021, to Apr 27, 2022, and included 61,344 residents aged 60 years or older across 626 long-term care facilities who were tested for SARS-CoV-2.Main outcomes were lab-confirmed infection, hospital admission, and death.

About 95% of recipients received the Moderna vaccine as the fourth dose.Among the 13,654 residents who tested positive for COVID-19, the marginal (added) effectiveness of a fourth dose 7 days or more after vaccination versus a third dose received 84 or more days previously was 19% (95% confidence interval, 12% to 26%) against infection, 31% (20% to 41%) against symptomatic infection, and 40% (24% to 52%) against severe outcomes, the authors found."Marginal effectiveness against all outcomes was lower when comparing fourth doses with third doses received less than 84 days previously, which broadly supports a three month minimum interval between third and fourth doses, although the optimal dosing interval remains unknown," the authors concluded."Vaccine effectiveness estimates (compared with unvaccinated residents) against infection (49%), symptomatic infection (69%), and severe outcomes (86%) related to the omicron variant were consistently higher for a fourth dose than for a third dose received 84 or more days previously." Jul 6 Br Med J studyJoint venture aims to develop targeted antibioticsGerman biopharmaceutical company Boehringer Ingleheim, German