How Public Health Guidelines Shifted, Conflicted as Pandemic Unfolded

As the COVID-19 pandemic emerged, scientists and public health officials struggled to gather the evidence necessary to craft meaningful mitigation guidelines.

In a new research letter based on a review of national and international guidelines, corresponding author Gabriel Birgand, PhD, discussed the ways in which those guidelines have varied, changed, and conflicted over time. Birgand is affiliated with Imperial College London, in the United Kingdom, and Nantes University Hospital, in France. The review was published in JAMA Network Open.

Birgand and colleagues said it is not surprising that there would be variation in the guidelines given the scientific uncertainty about how the SARS-CoV-2 virus spreads, particularly with regard to airborne transmission. However, he and his co-authors said the stakes are high when it comes to getting guidelines right.

“Variability among guidelines may generate confusion, anxiety, and mistrust among health care professionals (HCPs) regarding the ability of respiratory protection to prevent SARS-CoV-2 transmission,” they wrote.

The investigators looked for guidelines from public health agencies in 4 countries and from 2 international organizations, the World Health Organizations (WHO) and the European Center for Disease Prevention and Control. After exclusions due to study criteria, the investigators were left with a list of 59 guidelines published between January 1 and December 31 of last year. Those guidelines tell a story of shifting strategies.

For instance, at the start of the year, all guidelines recommended that health care providers wear respirators when in direct contact with a person with confirmed or suspected COVID-19. The next month, both the European CDC, followed by the American CDC, modified the recommendation to support the use of medical face masks when treating COVID-19 patients if respirators were not available. However, respirators were still the recommendation when providers were conducting aerosol-generating procedures. Other agencies, including the WHO, soon updated their guidelines similarly. However, insofar as those guidelines included recommendations specific to aerosol-generating procedures, Birgand and colleagues noted that the list of what constituted an “aerosol-generating procedure” varied, with lists ranging from 3 to 14 procedures. The most commonly included procedures were bronchoscopy and intubation.

“These discrepancies may reflect controversies related to SARS-CoV-2 transmission routes,” the authors said. “The most recent assessment of the clinical evidence for the risk of transmission of acute respiratory infections to HCPs caring for patients undergoing AGPs dates back to a 2012 systematic review of a limited volume of studies.”

Meanwhile, Germany in late March became the first country to recommend that all people entering a hospital wear a face mask, and it was soon followed by other countries. The authors said the relatively slow speed at which universal masking was adopted could be related to early confusion around asymptomatic transmission. New, stronger research is needed in order to better understand which procedures should be considered aerosol-generating, and how individual procedures might affect risk levels to HCPs treating patients with respiratory illnesses.

Finally, the investigators said, guidelines also appear to have been crafted in part to deal with resource limitations, which sometimes differed from country to country. The authors said better research and better collaboration could help eliminate such problems in the future.

“Inconsistencies in respiratory protection guidelines between neighboring countries created confusion over optimal measures,” they said. “Strong collaborations between national and international organizations are critical in such circumstances.”