New research evaluating the effect of eye protection on COVID-19 transmission among healthcare workers has found face shields may have a substantial protective effect, which could also be down to their additional inhalation protection.
The systemic review – published in Antimicrobial Resistance & Infection Control this month – examined available research, including five observational studies from the US, India, Colombia and the UK, that tested face shields, goggles, and wraparound eyewear on 7,567 healthcare workers.
The authors found that while eye protection may play a role in prevention of SARS-CoV-2 (the virus that causes COVID-19 disease) infection in healthcare workers, robust comparative trials were needed to clearly determine effectiveness of eye protections and wearability issues in both healthcare and general populations.
Further, all five studies examined were non-randomized, and did not adjust for potential confounders, making the overall risk of bias high. Therefore, the evidence summarised was of “very low certainty”.
However, the paper noted that the studies did provide suggestive evidence that face shields provide some protective effect, and that this may be substantial.
“These studies cannot determine how much of the protective effect is due to reduction of transmission from the eyes via nasolacrimal duct to nose,” the authors said.
“Furthermore, a face shield – the main protection used – may provide additional inhalation protection as seen in some of the laboratory studies. While goggles also provide eye protection, face shields will likely give substantial protection against inhalation of droplets as well as eye protection and are more comfortable to wear.”
As a result, they said face shields, in addition to masks, should be considered for higher risk situations, such as contact tracing, quarantine workers, and some primary care consultations, or when there is substantial COVID spread in the community.
“Additional protection is likely to be particularly important to healthcare workers in settings where currently only face masks are being used,” the authors concluded.