LAUSR

In 2020, many business meetings and academic conferences were canceled or became virtual because of uncertainties regarding SARS-CoV-2 transmission and strict public health measures. In fact, rates of SARS-CoV-2 transmission at large indoor gatherings have remained largely unknown, although some appeared to have been superspreader events for the virus (eg, the 2020 Biogen conference in Boston, Massachusetts). Earlier studies of SARS-CoV-2 outbreaks on cruise ships have indicated protective effects of reducing the number of individuals on board and testing passengers and crew.1,2 The rate of SARS-CoV-2 seroconversion after a medical conference in Switzerland in September 2020 with stringent masking, physical distancing, supervised hand hygiene, and canceling of social events was 0 of 168 (<1%) at a time of community incidence of 65/100 000 population per week (<0.1%).3 With the advent of SARS-CoV-2 vaccines, more recent studies on larger sporting and cultural events that were generally outdoors have shown that vaccination, previous COVID-19 infection, a negative lateral flow test within 48 hours of the event, and adequate mask wearing, often together with spaced seating, were associated with a low risk of infection after the event.4,5 However, cases of infection resulting from transmission during such events (possibly including recent medical conferences6) could not be totally prevented, particularly when community transmission of SARS-CoV-2 was high. The study by Silver et al7 in JAMA Network Open offers some hope for the future of relatively safe in-person meetings. The authors conducted a survey after a large hybrid medical congress in Florida in early February 2022, when transmission of the Omicron variant was most intense (ie, incidence rates >1000/100 000 population per week [>1%]), and noted no difference between in-person and virtual attendees. Meeting registrants attending the conference in person were strongly encouraged to self-test before traveling to the meeting and were required to have been vaccinated and to wear a surgical or N95 or KN95 mask at the meeting. Only spaced seating and outdoor catering were offered, and indoor social events were prohibited. Among 682 survey respondents (42.2% response rate), 12 reported a SARS-CoV-2–positive test the week after the meeting, with no significant differences between the 10 of 546 in-person and 2 of 135 virtual attendees (1.8% vs 1.5% [95% CI for the difference, −0.2% to 0.3%]). Should we now feel safe planning or attending in-person medical conferences and other events? Some physicians have argued conferences need to be extremely low risk to avoid ignominy.6 However, the high levels of in-person physician attendance at medical conferences demonstrate broad support for them. The COVID-19 pandemic remains dynamic and unpredictable. Evidence of relative safety in the past does not guarantee safety in the future. Key elements for safer large indoor gatherings include vaccination, testing, masking, and prioritizing events with mask removal to areas with appropriate ventilation. The exact use of each of these and whether they are voluntary or mandatory are subjective decisions that have to be made without much data. A flexible approach that adjusts for levels of community transmission at the time of the event is likely important. We believe hybrid conferences will become the new standard. Virtual congress technology is improving, and hybrid scientific conferences using them have been excellent. The number of participants often increases with hybrid conferences while the satisfaction and quality rating by attendees usually do not drop. A hybrid option helps junior academics, persons with a career break (eg, due to maternity or paternity leave, serious illness, care for close relatives, military service), and attendees from lowand middle-income countries. Reduced traveling will reduce the carbon + Related article