The World Health Organization (WHO) has issued a new guidance in the wake of increasing number of infections from the Omicron variant for the use of masks by health workers providing care to suspected or confirmed Covid-19 patients. These guidelines will supersede the recommendations provided earlier to prevent and control infection among healthcare workers who are attending to suspected or confirmed Covid-19 cases.
The guideline insists that the health worker should wear a respirator (FFP2, FFP3, NIOSH-approved N95, or equivalent or higher-level certified respirator) or a medical mask along with other personal protective equipment (PPE) – a gown, gloves and eye protection – before entering a room where there is a patient with suspected or confirmed Covid-19. This recommendation applies to any setting where care is provided to patients with suspected or confirmed Covid-19, including home care, long-term care facilities and community care settings.
The guideline emphasises the use of respirator along with other PPE by health workers performing aerosol-generating procedures (AGPs) and by health workers on duty in settings where AGPs are regularly performed on patients with suspected or confirmed Covid-19, such as intensive care units, semi-intensive care units or emergency departments.
It wants that the appropriate mask fitting should always undergo necessary quality checks like initial fit testing, seal check and methods to reduce air leakage around the mask.
However, the guideline clarifies that as of December 2, evidence on the effectiveness of respirators versus medical masks in healthcare settings is still limited to five observational studies that have important methodological limitations and inconsistent findings about whether respirators decrease the risk of Covid-19 infection.
The observational studies were conducted before the emergence of the Delta and Omicron variants and increasing vaccination uptake, the guideline states. It also adds that the comparative protective effectiveness of respirators compared to medical masks in settings without exposure to AGPs in the context of SARS-CoV-2 transmission continues to be a critical research question which has not been fully answered.
“Although there are limitations to the available evidence on respirators versus medical masks in healthcare facilities, data show that the Omicron variant is spreading significantly faster than the Delta variant in countries with documented community transmission, with a doubling time between 1.5-3 days. Preliminary, unpublished data show a reduction in neutralising titres against Omicron suggesting a level of immune evasion and an important reduction in vaccine effectiveness against infection and symptomatic disease for Omicron compared to Delta. Worldwide, the Omicron variant is spreading rapidly, and a high proportion of health workers are still unvaccinated and thus at high risk for infection and potentially, severe disease and death,” the guideline says.
It is in the light of such concerns of increased transmission of Omicron, potential immune escape and limited vaccination coverage in health and care workers around the world, WHO recommended the changes in usage of masks.
Even as it urges scaling up production, procurement and distribution of respirators and medical masks for use in health and care settings to ensure equitable access to respirators and medical masks by all health and care workers around the world, WHO suggests extended use of appropriate reprocessing of respirators in situations where the availability of respirators is limited or there are shortages.
“Regardless of the type of mask, appropriate mask use is critical to ensuring effectiveness and reducing the risk of transmission. Masks should be viewed as one key component of a comprehensive package of infection prevention and control (IPC) measures to be applied during health care when Covid-19 is suspected or confirmed,” WHO says.