Ask the Experts: Paxlovid for COVID-19; Biological vs. Mechanical Heart Valves; Bone Health for Vegetarians

I was quite sick with COVID-19 earlier this year, despite having been vaccinated. I have read that it is possible to be reinfected with Omicron more than once, but that a new antiviral medication can help. Can you tell me more about it?

Research suggests that the antiviral medication you refer to—a combination of nirmatrelvir and ritonavir (Paxlovid®)—is effective at reducing the risk of hospitalization and death, and may speed recovery from the virus as long as you start taking it within five days of symptom onset. The medication is recommended for people with mild-to-moderate illness who are at particular risk for severe COVID-19 (a group that includes older adults). The drug usually is well tolerated, but some people experience side effects, including an unpleasant taste in the mouth, a skin rash, muscle aches, and diarrhea; moreover, it interacts with statins, blood thinners, anti-arrhythmia medications, and some other drugs. The U.S. Food & Drug Administration recently authorized pharmacists to prescribe Paxlovid to people who have tested positive for COVID-19, but due to the possible side effects and interactions, I recommend you contact your doctor if you contract the virus again and want to try Paxlovid.

Rosanne M. Leipzig, MD, PhD

Geriatric Medicine

I’ve been told that I may need mitral valve replacement surgery. My understanding is that I can opt for a mechanical or biological replacement valve. Which is better?

Mitral valve disease can be treated with valve repair or valve replacement. If valve repair is not appropriate, the choice of valve replacement depends on many factors, Including age and other medical issues.

Mechanical replacement valves last longer—up to 30 years, in some cases—so if you are 60 or younger, this option might be better for you. However, mechanical valves are associated with a greater risk for blood clots, so people who have these valves need to take blood thinners for the rest of their lives. This typically means warfarin (Coumadin®), and since the drug has numerous drug and food interactions, people who take it need to watch their diet and avoid taking certain medications. They also need regular blood tests to make sure their blood is clotting properly.

Biological valves come from human donors or animal tissue (cow or pig), or are made primarily from non-metal components. These valves don’t always last as long as mechanical options—in some cases 10 to 15 years or fewer (for reasons that are unclear, they tend to have shorter lifespans in younger people). They are less likely to cause blood clots than mechanical valves, so you won’t require lifelong blood thinners, although you may be prescribed one to prevent clotting in the first 90 days or so after the surgery. For this reason, biological valves may be a better option for people who can’t take warfarin or would rather not take it.

Because there are so many factors that may impact your choice, this decision usually requires a discussion with your cardiologist and cardiac surgeon. You may benefit from more than one medical opinion.

Bruce Darrow, MD, PhD


I’m a vegetarian and recently read that it puts me at greater risk of hip fractures. I drink milk with my diet. What can I eat to prevent fractures?

A recent study (BMC Medicine, Aug. 11) does point to a greater risk of hip fractures in women who don’t eat meat. The increased risk may be due to the fact that vegetarian women often are underweight, which is associated with lower bone strength. Meat and fish contain nutrients that contribute to bone health (most specifically protein, vitamin D, and vitamin B12), and these may be lacking in vegetarians. Foods to eat that will compensate are soybeans, eggs, nuts, and tofu, as well as skim or low-fat milk, nonfat or low-fat yogurt, part-skim cheeses, soy milk, or unsweetened almond milks with added calcium. It also is important to maintain an adequate fruit and vegetable intake, with an emphasis on green leafy vegetables. If drinking juice, choose an option that is fortified with vitamin D. Get plenty of resistance exercise too (such as lifting weights), as this boosts bone strength.

Fran Grossman, RDN, MS, CDECS, CDN


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UHN Staff

University Health News is produced by the award-winning editors and authors of Belvoir Media Group’s Health & Wellness Division. Headquartered in Norwalk, Conn., with editorial offices in Florida, Cleveland, Pittsburgh, … Read More

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