There are a lot of questions surrounding COVID-19. also known as the novel coronavirus.

© Bertrand Blay | iStock / Getty Images Plus

My daughter ordered takeout food several times during the COVID-19 outbreak in her city. She wanted to support local restaurants, but I was concerned she might catch the virus if the food was prepared by somebody who was carrying it. Is this possible?

Assuming the restaurants your daughter was ordering from are compliant with recommended hygiene protocols, the takeout food should be safe. Hopefully the restaurant managers were monitoring staff for any symptoms that might indicate COVID-19. Ongoing, there are precautions your daughter and you might want to consider following when ordering any takeout food. For example, it’s worth ordering takeout a day ahead, removing it from the delivery container onto a plate or into another container, and storing it in the refrigerator until you consume it, since the additional time can help ensure that bacteria die off. When reheating the food, be sure to heat it until it is sufficiently hot (at least 165 degrees Fahrenheit) to destroy any bacteria, including COVID-19 (incidentally, the same applies to reheating leftovers from meals you’ve prepared yourself using fresh ingredients). And, of course—thoroughly wash your hands prior to eating.

Who is most at risk of complications from COVID-19 if the outbreak continues or recurs?

Most people who develop COVID-19 develop relatively mild symptoms (such as low-grade fever, cough, slight shortness of breath, muscle aches, and nausea). However, some groups are known to be at greater risk of severe pneumonia-like symptoms due to COVID-19. This includes the elderly, people with asthma, chronic obstructive lung disease and other lung diseases, and/or those who are immunocompromised because of diseases like cancer and HIV. People who take medications that suppress the immune system (such as those used to treat cancer and autoimmune conditions like rheumatoid arthritis) also are particularly vulnerable to COVID-19 complications, as are those who smoke.

Is it possible for people who have had COVID-19 and recovered to still be infectious even though they are no longer showing symptoms?

We’re still learning about COVID-19, but a small study carried out in China suggests that some people may continue to carry the virus for up to a week after their symptoms have completely disappeared. At time of writing, we don’t know whether the virus is still capable of transmission in its later stages, but most experts were recommending that symptomatic individuals self-quarantine for two weeks after recovering.

It was confusing to be told that the general public shouldn’t bother wearing masks, and then be told we should. Why did the advice change?

You’ll likely be aware that masks were in high demand for medical staff coming into contact with many people suffering from COVID-19. In those frontline situations, masks help protect healthcare providers from continuing heavy exposure to COVID-19 and other viruses. Initially there wasn’t much evidence that masks could help prevent the spread of the virus in the community. However, as time passed we learned that asymptomatic people with the virus can pass it on, hence the federal government updated its advice.

If the COVID-19 outbreak should worsen or recur, what can I do to ensure my home-made mask offers the best protection?

One of the reasons experts were skeptical that masks would protect the general public against COVID-19 is that home-made fabric masks moisten when worn for extended periods of time. This might aid in the spread of COVID-19 if an asymptomatic person touched the mask while they were out, and then touched a hard surface, such as a grocery store cart. You can best avoid this by washing the mask in hot, soapy water after you wear it (and be sure to wash your hands after removing the mask). When wearing a home-made mask, ensure that it covers your nose and mouth, preferably without being pressed tightly against your lips. Keep in mind too, that most experts say that frequent handwashing, avoiding touching your face, social distancing, and self-quarantine for the ill remain the most effective methods of protecting against COVID-19 and preventing its spread.

I was alarmed to read that COVID-19 could damage the brain. How is this possible?

You are likely referring to a report that COVID-19 might result in encephalopathy, which is defined as a brain disease that alters brain function or structure. While most people with COVID-19 developed respiratory symptoms, some also had neurologic manifestations, including brain swelling, seizures, confusion, and memory issues. However, symptoms such as these are extremely rare and actually can occur with any virus—including influenza—not just with COVID-19.

Around the time COVID-19 was rampant in my neighborhood, I suffered unexplained nausea and diarrhea for several days. A friend now tells me my symptoms might have been due to the virus. Is it possible to have COVID-19 and not have respiratory symptoms?

Many illnesses can cause gastrointestinal symptoms, and most instances of new-onset nausea and diarrhea are not due to COVID-19. However, a small Chinese study did suggest that some people with mild cases of COVID-19 had gastrointestinal symptoms only. It is important to be aware that COVID-19 may present with the symptoms you describe, since they can trigger the need for self-quarantine. In the study, diarrhea reported by the participants had an average duration of more than five days, with a frequency of about four bowel movements a day. I recommend that any older adult with diarrhea that continues for more than 24 hours contact their doctor, since diarrhea also can result in potentially serious dehydration.