Readers' questions about masks continue


Hello again, dear readers, and welcome back to our monthly letters column. You’ve kept our inbox lively this month, so we’ll dive right into your questions and comments.

-- A reader in Oregon, where ongoing wildfires have created dangerous air quality, wondered about masks. “Will our masks that we wear for COVID help us with the wildfire smoke here?” they asked. The answer depends on the type of mask you’re using. The cloth masks we’re using to slow the spread of the novel coronavirus don’t offer much protection from wildfire smoke. Although cloth masks can block the respiratory droplets that the virus travels on, they’re not an efficient barrier against the infinitely smaller particulates in wildfire smoke. That requires the close weave of N95 masks, which remain in short supply. Without an appropriate mask, it’s best to stay indoors with windows and doors closed, and run an air purifier if you have one.

Elizabeth Ko, MD and Eve Glazier, MD

-- The wildfire smoke question actually contains the answer to another reader’s mask question. “How is it possible for a mask to be effective against the virus?” they asked. “The virus is so small that it must be able to fit through a mask.” You’re correct that the virus itself is microscopically small enough to fit through a cloth mask. However, a virus can’t move on its own. The novel coronavirus travels via the respiratory droplets from an infected person’s cough, sneeze or breath. Due to their size, those respiratory droplets can be blocked by a multi-layer cloth mask. When used along with social distancing to stay out of range of another person’s droplet emissions, a mask can indeed reduce the risk of spreading and encountering the virus.

-- A reader from Oklahoma had a question in response to a column about alpha gal syndrome. This is when someone who was bitten by the Lone Star tick develops an allergy to red meat. “Why doesn’t anyone ever mention that gelatin can cause a reaction when you have alpha gal?” they wrote. “I’ve had the allergy for 10 years, and my one and only (allergic reaction) came from consuming gelatin capsules.” Thank you for your reminder that some people with alpha gal syndrome do become sensitized to gelatin, which is a protein obtained from animal byproducts. And, as you mention, gelatin can be present in capsules and is used in some medications as a stabilizer. As with all allergies, people living with alpha gal syndrome need to be alert to all potential triggers.

-- In response to a column that mentioned asymptomatic transmission of the coronavirus, a reader wondered if the terminology should be adjusted. “Doesn’t the term ‘pre-symptomatic’ better describe what is happening?” Actually, both terms are accurate. Some people infected with the novel coronavirus never develop symptoms. If they pass along the virus, it’s asymptomatic transmission. Pre-symptomatic transmission occurs when someone passes along the virus while in good health and then later develops symptoms.

Thank you to everyone for your letters and kind thoughts -- they mean a lot to us. We hope you and your loved ones stay safe and well.

(Send your questions to [email protected]. Owing to the volume of mail, personal replies cannot be provided.)