Hello, dear readers, and welcome to an extension of our monthly letters column. Our main letters column this month was devoted to your questions about the new coronavirus vaccine -- an important topic that needed immediate attention. So we’re back with parts one and two of a bonus edition to help catch up with your more general questions. Onward to part one!

-- A reader from Cleveland asked if eating carrots helps with prostate health. “Have you ever heard of this?” he asked. “How many carrots do you have to eat?” While a potential link between eating carrots and prostate health has been a subject of interest for a number of years, the research remains inconclusive. Some studies have found a link between alpha-carotene, a nutrient in carrots, and a decrease in prostate cancer risk. The studies found eating a medium-sized carrot each day, or drinking freshly pressed carrot juice, to be helpful. However, those results haven’t been universally duplicated. If you’re going to try it, we recommend eating your carrots, because the crude fiber they contain is beneficial to the gut.

-- In a column about why falling is a serious health risk for older adults, a reader from Fresno, California, asked for a clarification. “You wrote that just a sprain or a bruise can interfere with quality of life,” she wrote. “Can you elaborate?” Although a big concern with falls is breaking a bone, even a mild injury can alter someone’s routine. A sprained ankle makes it difficult to get around. Small tasks like going to the mailbox, or even walking from room to room, can become daunting. The aches and pain of a bruise can limit movement, so basic actions like reaching up to a kitchen shelf or dressing oneself become more difficult. These limits are temporary, of course, since sprains and bruises heal. But, in the meantime, daily life is adversely affected.

-- A reader near Austin, Texas, who recently cared for her father and two aunts at the ends of their lives, noticed that dentists would sometimes suggest procedures that were out of step with the needs and abilities of an older adult. “Do keep up with cleanings and care for cavities, but get a second opinion for things like tooth extractions and implants,” she wrote. “Some older senior citizens may not be healthy enough for these procedures, which the dentist may not know, or they may not have the money to afford them.” We think that’s very good advice. A second opinion can clarify a medical or dental issue and help ensure that only necessary care is performed. Thank you for sharing.

-- A reader from Tulsa, Oklahoma, got right to the point with his question: “Is it possible for mosquitoes to pass on COVID-19?” So far, there are no known cases of the new coronavirus being transmitted via a mosquito bite. It’s a respiratory virus, and its main form of transmission is through the droplets from a cough or sneeze and the smaller particles released when we speak or exhale.

See you in a few days with bonus questions in part two.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I’m a 60-year-old woman with naturally fair skin. I’ve worked outdoors all of my life -- and now I have the age spots on my face to prove it. Why do they happen? Are there any creams from the drugstore that might help to fade them?

Dear Reader: Age spots are the darkened areas of skin that develop on parts of the body that have been regularly exposed to sunlight. They often appear on the shoulders, backs of the hands, arms, back and face. People who are balding and don’t regularly wear head coverings while outside may develop them on their scalps.

Age spots often look like freckles of varying sizes, and they range in color from light tan to dark brown. While it’s true that age spots, which are sometimes referred to as sun spots or liver spots, become more common as we get older, they can appear on any skin that has had chronic overexposure to sunlight.

When you develop age spots, it’s your skin’s way of letting you know you’ve gotten too much sun. They form in response to UV light, which accelerates pigment production. Unlike cancerous and pre-cancerous growths, which they can resemble, age spots don’t require medical treatment. However, for cosmetic reasons, many people prefer that they be removed, or at least lightened.

Treatments vary. Fade creams and lotions typically use hydroquinone, glycolic acid or kojic acid. Nonprescription versions of these products are available at your local drugstore. More powerful fade creams, with higher concentrations of the active ingredients, are available by prescription. While they tend to lighten the spots, they may not completely remove them. Plus, you have to be patient. It can take weeks, or even a few months, of consistent use to see an improvement. Even when using nonprescription fade creams, it’s a good idea to get guidance from your health care provider, since the active agents can cause side effects.

For more complete results, there’s laser therapy, which targets and destroys specific pigments. Cryotherapy, which involves freezing the skin, and acid peels, to exfoliate the skin, are also sometimes used. Each of these can cause side effects, such as pain, excessive dryness, blistering, redness and swelling.

Whichever approach you take, it’s crucial to also stop exposing your skin to sunlight. Use a full-spectrum sunscreen, stay in the shade and cover your skin. That means wearing long sleeves, long pants, hats, scarves or gloves as needed. Some of our patients have invested in SPF clothing, which they find quite helpful. Others use an umbrella to block the sun while outdoors.

Unless you take steps to minimize sun exposure, age spots will return, and new ones may form. It’s also important to note that some cancerous and pre-cancerous growths can start out looking like age spots. We recommend that all adults regularly monitor the moles, marks and birthmarks on their skin for changes in size, color, shape and texture. This should be in addition to an annual skin cancer screening by a health care professional, which is a visual exam that is often covered by insurance.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I don’t think I’m the only one wondering how the new coronavirus vaccines got developed so fast when other vaccines in the past took so much longer. Can you please explain?

Dear Reader: When the quest for a safe and effective coronavirus vaccine began, early in 2020, we had only previous vaccine development to guide our expectations. And you’re correct, those vaccines -- against diseases such as polio, measles, smallpox and chickenpox -- took years, or even decades, to develop.

Until now, the fastest timeline was the four years it took to develop the mumps vaccine. Yet less than a year into the current effort, two highly effective preparations have received emergency-use approval from the Food and Drug Administration. This is due to multiple factors. A crucial one is international cooperation, which resulted in the immediate sharing of the genetic sequence of this never-before-seen virus. Additionally, the global health crisis prompted abundant funding.

But perhaps most important was the nature of the virus itself. Coronaviruses get their name from the distinctive “crown” of club-shaped spike proteins on their outer surface. Thanks to years of previous research, we know that the virus uses these proteins to enter human cells. Also immensely helpful was the fact that COVID-19 is quite similar to SARS and MERS, each of them coronaviruses that also originated in animals and jumped to humans. In developing the new coronavirus vaccines, scientists were building on an existing body of knowledge.

Unlike previous vaccines, which used a weakened or inactivated virus to trigger an immune response, the new vaccines harness the molecular building blocks of the novel coronavirus. Specifically, they use a single strand of genetic code known as messenger RNA, or mRNA. The genetic code teaches human cells to build a harmless fragment of the spike protein, just enough for the immune system to recognize the coronavirus. This triggers a robust response that deactivates the spike protein. Because that spike protein is how the coronavirus penetrates a cell, disabling it prevents infection. And, because there are multiple ways to deploy mRNA, multiple vaccines are now in different stages of development. That’s also why, when you get the first of the two-dose vaccine regimen, you have to follow up with the same vaccine. You can’t mix and match.

Both approved vaccines have impressive efficacy of 94% to 95%. The numbers are a bit lower for people 65 and older, but it’s believed that may reflect the smaller sample size of clinical trial volunteers in that age group. As with many vaccines, this one has several side effects. Some people receiving the shots report experiencing pain at the injection site, headache, fatigue, pain in the muscles or joints, chills and mild fever. Several people have experienced severe reactions to the vaccine, but those cases were rare.

These new coronavirus vaccines are game-changers. In light of the dangers posed by COVID-19, as well as the lingering effects of the illness, we hope that when the vaccine becomes available to you, you will choose to get immunized.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)