In a significant finding, a study conducted by a city-based physician has revealed that health workers directly interacting with family members/contacts of COVID-19 patients tested positive for the infection, despite using hand sanitisers, face masks and gloves, among other things. The use of face shield, in addition to face mask and other personal protective equipment (PPE), was, however, found to be effective in safeguarding the workers from the virus.
A study conducted by M. Emmanuel Bhaskar, Professor of Medicine, Sri Ramachandra Medical College & Research Institute, and his research fellow Santhanam Arun on “SARS-CoV-2 infection among community health workers in India before and after the use of face shields” was published in the Journal of the American Medical Association a couple of days ago.
The research was based on the belief that COVID-19 was transmitted predominantly through respiratory droplets from infected persons in close proximity to uninfected persons, although airborne transmission may also play a role. On May 3, community health workers from a research network in Chennai were assigned to counsel asymptomatic family members/contacts of patients who had tested positive for the infection, at their residences.
The team, comprising 62 workers, including 40 women, were housed in separate rooms in hostels and provided food. They were not allowed to visit their houses or public places outside work, and they communicated with each other or their supervisors over phone.
Before they commenced the duties as part of the study, all workers tested negative for the virus. PPE included alcohol hand rubs, 3-layered surgical masks, gloves and shoe covers.
“Standing 6 ft away, the workers explained to the contacts the principles of quarantine, mask use, physical distancing, hand washing and symptoms of the infection. Family members were asked to wear face masks during the conversation, although the workers reported that some did not,” Dr. Emmanuel said.
After some workers developed symptoms of COVID-19, face shields made of polyethylene terephthalate (250-m thickness) were added to the PPE provided. After each visit, the shield was decontaminated using an alcohol-based solution, and at the end of the day, soaked in detergent mixed with water. After the introduction of face shields, workers were screened for symptoms and they underwent weekly RT-PCR tests.
Shield effective
Before the introduction of face shields, between May 4 and 13, 62 workers visited 5,880 homes with 31,164 persons. Among the persons counselled, 222 persons tested positive for COVID-19. Among the workers, 12 (19%) were infected during the period. Eight developed symptoms (fever, cough, sore throat, myalgia and anosmia) and four others were asymptomatic. The 12 infected workers were moved to care centers, where four developed desaturation and mild breathing difficulties. They were treated with oral hydroxychloroquine and oxygen therapy, and they recovered.
After face shields were given to the workers, the remaining 50 continued providing counselling. They visited 18,228 homes, and of the 1,18,428 persons counselled, 2,682 tested positive for the virus. No worker contracted the infection.
The study found no infection among the health workers after the addition of face shields to PPE. The shields may have reduced ocular exposure or the contamination of masks or hands, or may have diverted the movement of air around the face.
“I want to make it clear that face shields are not replacements for masks… it has to be worn along with it. It should be cleaned properly after use. The research is focused on frontline health workers and not the public. Since police personnel are also at the forefront in combating COVID-19, they too can consider wearing face shields along with face masks,” Dr. Emmanuel said.
