News Scan for May 25, 2022

COVID-19 vaccination tied to less disease spread, shorter virus sheddingTransmission of COVID-19 was significantly lower, and viable virus was detected for a shorter period, in fully vaccinated patients and staff isolated at a South Korean hospital than in their partially vaccinated and unvaccinated counterparts, finds a study published yesterday in JAMA Network Open.A team led by researchers from the University of Ulsan in Seoul studied SARS-CoV-2 transmission among 173 healthcare workers, patients, and guardians diagnosed as having mild COVID-19 from Mar 1, 2020, to Nov 6, 2021.

The team also measured viral RNA with polymerase chain reaction and cultured daily saliva samples from 45 patients infected with the Delta variant from Jul 20 to Aug 20, 2021, to measure virus load and shedding.Among the 173 adults in the transmission study, the median age was 47 years, 58% were women, and 29% were fully vaccinated against COVID-19.

Secondary transmission was significantly less common among vaccinated than unvaccinated participants (3 of 43 [7%] vs 29 of 110 [26%]).Median age among the 45 Delta-infected participants was 37 years, 31% were women, 13% were fully vaccinated, and 87% were partially vaccinated or unvaccinated.

Although the initial viral RNA load was comparable between both groups, viable virus in cell culture was detected for substantially longer in partially vaccinated or unvaccinated participants than in the fully vaccinated (8 vs 10 vs 4 days, respectively)."Data from this study provide important evidence that despite the possibility of breakthrough infections, COVID-19 vaccinations remain critically useful for controlling the spread of SARS-CoV-2," the study authors wrote.In a related commentary, Camden Gowler,