Dear Doctors: I live in Boston, and the news here seems to be fixated on a brand-new COVID-19 variant. Omicron was all everyone talked about for a long time. Does this mean the new variant we are hearing about is worse? What are we supposed to do to protect ourselves?

Dear Reader: You’re referring to XBB.1.5, an offshoot of the omicron variant. Omicron is itself one of the numerous descendants of SARS-CoV-2, the novel coronavirus that launched the COVID-19 pandemic three years ago. The reason you’re hearing so much about this new variant, which is being referred to simply as XBB, is that it has become the dominant strain of the novel coronavirus in your area.

According to the Centers for Disease Control and Prevention, genetic testing suggests that the majority of new cases of COVID-19 in the northeastern U.S. are now caused by XBB. Nationally, XBB has gone from causing fewer than 2% of COVID-19 cases at the end of 2022 to more than one-fourth of all cases at the start of 2023.

As with all viral variants that begin to circulate in great numbers, the success of XBB is due to the presence of certain mutations. In coronavirus variants, mutations include changes to the spike proteins on the outer shell. These structural changes make the variants more successful at slipping past the body’s existing defenses. This includes evading both naturally acquired immunity and immunity conferred by vaccines and boosters.

While XBB has proven to be more contagious than its predecessors, it does not appear to be more dangerous. At this time, there has not been a spike in either hospitalizations or deaths due to XBB infections. However, this will likely change as the variant continues its geographic spread.

What’s particularly worrisome is that XBB has arrived at a time when vaccination rates against COVID-19 have dropped precipitously. Only 15% of those who are eligible have received the newer bivalent vaccine, which was developed with the variants in mind. On top of that, the majority of people in the U.S. have largely stopped taking protective measures, including the use of masks. That, along with indoor living that is necessitated by the cold winter weather, has increased the risk of infection.

And that brings us to your final question, which is how to guard against infection with XBB. The answer is to get back to the basics. It’s crucial to stay up to date with coronavirus vaccines and boosters, which have proven to be effective in protecting against severe illness. We urge anyone who hasn’t yet received the bivalent booster to do so. When spending time in public places, wear a good-quality and well-fitted mask. If you do become sick with COVID-19, see your doctor. Antiviral medications can ease symptoms and shorten the duration of illness. The coronavirus and its variants are with us for the foreseeable future. It’s up to us to remain vigilant and protect ourselves and those around us.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I have shared my home with pets my whole life. I am now a 76-year-old widow, and my menagerie is down to two small dogs. I just saw on the news that pets keep you mentally sharp. Is that true? I’d like to be able to reassure my sons that my furry companions are a boon and not a burden.

Dear Reader: We’re happy to report that a wealth of research continues to find that living with a companion animal is associated with a wide range of benefits. These include enhancing the pet owner’s physical, emotional and mental health, and generally improving their quality of life.

We suspect that the news report you saw was tied to a recent study that focused on pet ownership among older adults. The results, which were published last summer in the Journal of Aging and Health, suggest that growing older while living with a companion animal can play a role in preserving cognitive function. In their study, the researchers used data gathered by the Health and Retirement Study, an ongoing investigative project that involves about 20,000 adults in the United States, all of them 50 years of age or older. The researchers regularly conduct in-depth interviews with the participants and use tests and other diagnostic tools to amass data about aging. This includes details about physical health, social life, family life, employment, mental health and changes to cognition.

In the pet study you’re asking about, the researchers focused on 1,369 adults who did not have any existing cognitive problems. The participants were divided into three categories -- those without a pet, those whose pet had been with them fewer than five years and those living with a pet for five years or more. When the researchers analyzed the cognitive data collected over the course of six years, a surprising connection to pet ownership emerged. Those individuals who lived with a pet performed better on tests that measured both long- and short-term memory than did people of the same age but who did not live with a pet. This beneficial effect of living with a companion animal was even more pronounced in people whose pets had been with them five or more years. Interestingly, this protective effect was seen only in study participants who were 65 years of age or older. That’s the age at which it becomes more likely for the symptoms of either cognitive decline or dementia to begin to manifest.

As for why living with a companion animal appears to benefit cognition, the researchers suspect several factors may be at play. Health data showed that the pet owners in the study tended to have lower body fat percentages, better blood pressure and a lower incidence of diabetes than those without pets. This pointed to greater levels of physical activity, which has long been linked to improved cognitive health. The group with pets also reported lower levels of stress, anxiety, depression and loneliness, each of which have been shown to adversely affect mental function. We hope this helps you explain to your sons that your dogs are not only a bright spot in your life, but quite possibly just what the doctor ordered.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: My sister was diagnosed with cancer, and her doctors say she should consider freezing her eggs. It’s not definite that the treatment will affect her ability to get pregnant, but it’s a real possibility. I don’t know how freezing one’s eggs works. Can you explain? Is it expensive?

Dear Reader: Unfortunately, it’s true that certain medical treatments can, in addition to saving the person’s life, adversely affect their future fertility. This can occur in both women and men. For men, an option to preserve fertility is to freeze their sperm.

Women who wish to safeguard their future ability to have children can opt to freeze their eggs. The technical term for this is oocyte cryopreservation. The process was developed in the 1980s, with the first birth from a frozen oocyte taking place in Australia in 1986. In the decades since, the techniques have been refined. Today, oocyte cryopreservation has moved from an experimental procedure to an accepted treatment. It is so widely used that some large employers cover the procedure in their employee health insurance plans.

If your sister chooses to move forward with freezing her eggs, she will begin by seeking out the professionals who will help her. That means an experienced fertility specialist and a reputable reproductive clinic, preferably with an on-site lab. The medical team overseeing her cancer care may be able to offer recommendations.

The actual process begins with one or more prep appointments. These typically include an office meeting to explain the procedure, answer questions and fill out paperwork related to the process. Patients also undergo a blood draw to determine certain hormone levels and have a transvaginal ultrasound to allow the doctor to visualize the ovaries. In order for the ovaries to release multiple eggs, patients are prescribed synthetic hormones with which to inject themselves. This is known as ovarian stimulation, and it takes place on a precise schedule.

Over the next few weeks, patients return to the clinic for further blood tests and ultrasounds. These are used to track the body’s response to the injections. When the eggs are ready to be retrieved, the patient receives an injection of a medication that helps the eggs mature. Retrieval takes place at the clinic, with the patient under sedation. Guided by ultrasound imaging, the doctor uses a needle to pierce the sac that contains the egg. A suction device helps to gently remove it. The harvested eggs are then cooled to a subzero temperature and placed in a specialized storage facility, where they are preserved until needed.

The process of oocyte cryopreservation can help preserve fertility, but your sister will be advised that it isn’t foolproof. It can also be costly. When not covered by insurance, egg freezing can range from about $10,000 to more than $20,000 per cycle. Multiple cycles can be needed in order to collect enough eggs. Additional costs include an annual fee to store the eggs and the fee for in vitro fertilization when it comes time to use them.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)