Since May, the emergence of highly contagious “FLiRT” coronavirus variants—new mutations of Omicron—has led to a surge in infections and increased visits to emergency rooms. Wastewater treatment plants have reported virus levels that have quadrupled during this period.
Health officials in the Bay Area and California emphasize that face masks are a vital tool in preventing the spread of COVID-19, yet confusion and misinformation persist regarding their effective use.
With approximately 70% of Americans having received at least two doses of a COVID vaccine, many may be inclined to abandon mask-wearing altogether. However, Dr. Peter Chin-Hong, an infectious disease expert at UC San Francisco, provides insight on the matter.
Dr. Chin-Hong states that staying current with vaccinations is the most important protective measure against COVID-19. Research indicates that recent vaccines are about 70% effective in preventing severe illness, hospitalization, and long COVID. For unvaccinated individuals, early treatment with antiviral medications like Paxlovid or remdesivir can also lower the risk of hospitalization.
Regarding mask usage, the necessity depends on individual circumstances, risk factors, and the current hospitalization context. During high hospitalization rates, everyone should wear a high-quality mask. When hospitalizations are moderate, those at high risk—such as individuals over 65, immunocompromised persons, unvaccinated individuals, or those not up to date on booster shots—should wear masks in crowded indoor spaces, including public transit and airports. In areas with low hospitalization rates, mask-wearing is a personal choice, especially in indoor public transport. Individuals living with high-risk persons should consider masking for added protection, regardless of their vaccination status.
In California, community COVID-19 levels can be monitored through wastewater data.
Masks may still be required in places where transmissions are more likely, such as hospitals, shelters, and assisted living facilities, regardless of case numbers.
In cases of suspected COVID-19 or confirmed diagnosis, wearing a mask is essential for at least five days.
Dr. Chin-Hong highlights that high-quality masks effectively reduce the transmission of COVID-19, particularly when combined with other preventive strategies such as social distancing and proper hand hygiene. While no mask offers complete protection, both their design and wear matters significantly.
The primary mode of COVID-19 transmission is via respiratory droplets released when an infected person talks, coughs, or sneezes. Masks help block these droplets, thereby minimizing transmission.
For optimal protection, Dr. Chin-Hong recommends using medical N95, KN95, or KF94 masks, which filter many airborne particles. Masks with valves should be avoided since they allow unfiltered breath to escape. While disposable surgical masks are less effective compared to N95 variants, they still diminish transmission risk if they fit well. Cloth masks are a last resort but are better than not wearing a mask at all. Combining a surgical mask with a cloth mask can enhance its effectiveness.
Proper mask usage involves ensuring it covers both the nose and mouth comfortably without any gaps. Hands should be washed before putting on a mask, and the mask should not be touched while worn. It should be removed using the ear loops or ties, taking care not to touch the front.
Regarding usage frequency, clean and undamaged N95, KN95, or KF94 masks can be worn for several days. Surgical masks are designed for single use, but reusing one is still preferable to going without. Cloth masks should be washed after every use and can be dried in a dryer on high heat.
Wearing a mask for long durations can sometimes lead to skin irritation or acne, which can be mitigated by maintaining cleanliness and proper skincare.
Concerns about carbon dioxide poisoning from mask-wearing are unfounded; the accumulation of carbon dioxide within masks is minimal and not harmful.
For those who contract COVID-19, especially individuals aged 12 and older at high risk, discussing eligibility for antiviral treatments like Paxlovid with a healthcare provider is crucial. If taken within the first five days of symptom onset, Paxlovid can significantly reduce the chances of severe illness and hospitalization, representing a 90% prevention rate for high-risk cases.
With COVID-19 remaining prevalent, wearing a mask can effectively prevent infection, allowing individuals to avoid illness and its associated disruptions, while also providing protection against other respiratory viruses like colds and flu.
This article has been updated with the latest information and was initially published on May 31, 2023.