COVID-mitigating behavior didn't change after vaccination, study says
COVID-mitigating behavior such as physical distancing and mask use didn't change after receipt of vaccination prior to government exemptions, according to a research letter published yesterday in JAMA Network Open.
The researchers looked at the self-reported behaviors of 80,305 people who were fully vaccinated, partially vaccinated, or not vaccinated at all from Feb 23 to Jun 1. Respondents were from Canada, Denmark, France, Germany, Israel, Italy, Norway, Singapore, Spain, Sweden, the United Kingdom, and the United States, of whom 51.8% were women. The mean age was 47.8 years.
Regression modeling showed no difference in physical distancing between those with one or no vaccination dose across country and region matching (βs = –0.02 and –0.02, respectively). The models showed a difference among those who received two doses compared with those who had fewer, however. Those who were fully vaccinated physically distanced less than respondents with one dose (significant β for country matching [–0.08] but not region matching) and those who hadn't received any dose (βs = –0.07 for country matching and –0.12 for region matching).
No significant differences were seen regarding mask use in the aggregated sample.
The researchers note that when President Joe Biden said fully vaccinated adults didn't need to wear masks or physically distance, behavior still followed the same patterns.
"Despite occasional significant results, all of small magnitude, overall, this cross-sectional study found no substantial reduction in physical distancing or mask use associated with receipt of COVID-19 vaccine doses," write the researchers. "This suggests that until early June, people generally did not engage in concerning levels of risk compensation as they acquired immunity."
Oct 26 JAMA Netw Open research letter
Facemask ventilation in surgery may not be aerosol-generating procedure
Facemask ventilation of patients during routine surgery should not be considered an aerosol-generating procedure, according to a study published yesterday in Anaesthesia. If facemask ventilation lost this designation, it would not require extra personal protective equipment nor the sometimes half-hour delay between surgeries while the operating theater's air is ventilated.
The researchers compared 11 UK patients' aerosol generation during 60 seconds of tidal breathing and three coughs with aerosol generation during facemask ventilation with and without a deliberate leak. Breathing or coughing had a median of 191 particles per liter, while facemask ventilation with a leak produced 3 particles per liter, an almost 64-fold difference.
When the procedure included a deliberate facemask leak, aerosol generation was 17 times lower than normal breathing or coughing, at 11 particles per liter. Furthermore, coughing produced 1,260 particles per liter, while peak levels for regular facemask ventilation with or without an international leak were 120 and 60 particles per liter, respectively.
"The low concentration of aerosol detected during facemask ventilation with an intentional leak is also reassuring given that this represents a worst-case scenario," write the researchers. "On the basis of this evidence, we argue facemask ventilation should not be considered an aerosol-generating procedure," write the researchers.
In a press release by the Association of Anaesthetists of Great Britain and Ireland (AAGBI), its president Mike Nathanson, MBBS, MRCP, FRCA, added, "As we enter another winter, and with a high prevalence of Covid, the backlog of surgical cases is increasing. Anaesthetists will wish to carry on working for as many of their patients as possible. As the authors suggest, this research will inform the debate on how we can work safely."