The coronavirus subvariant JN.1 is now the fastest-growing strain of the virus in the United States. The strain now constitutes about 20% of new Covid-19 infections, according to the US Centers for Disease Control and Prevention. In the Northeast, JN.1 has become the dominant variant.

Meanwhile, the CDC has issued an alert to clinicians about the need to increase immunizations for influenza, COVID-19, and respiratory syncytial virus, or RSV. The public health agency reported that in the past four weeks, hospitalizations across all age groups increased by 200% for influenza, 60% for RSV and 51% for COVID-19.

This rise in infections is coming just before the holidays, when families across the country are planning get-togethers. What should people know about the winter viruses that are causing hospitals to fill up once again? What precautions should individuals be taking this holiday season? What should people keep in mind as they are traveling? And what additional steps can event organizers take to help reduce the chance of viruses spreading?

To help us with these questions, I spoke with CNN wellness medical expert Dr. Leana Wen, who is an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She previously served as Baltimore’s health commissioner.

CNN: Let’s begin with the coronavirus. What should people know about the JN.1 subvariant?

Dr. Leana Wen: The JN.1 subvariant is a descendant of another subvariant, BA.2.86. Both are part of the Omicron strain that has been dominant since 2022. JN.1 has already spread across parts of Europe and Asia, and is now rapidly gaining a foothold in the US.

The good news is that the tools we have should still be effective against JN.1. And we have many more tools against the coronavirus than we did two winters ago. The updated coronavirus vaccine is widely available, as are antiviral treatments, such as Paxlovid. The CDC alert to clinicians discussed the importance of urging patients to be up-to-date on their vaccines as well as to make use of available treatments. Together, vaccines and treatments are highly effective in reducing severe illness, which will also help alleviate the strain that many hospitals are facing.

CNN: What about the flu and RSV? Why is it important for people to also get vaccinated against these viruses?

Wen: Hospitalizations for the flu and RSV are also climbing. There are safe and effective vaccines available for both, but vaccination rates remain low.

According to the CDC’s clinician alert, as of November 18, there were 7.4 million fewer influenza vaccine doses administered to adults in pharmacies and physician offices compared with the 2022-2023 influenza season. Childhood flu vaccination rates are also lagging; they are at under 36% this year, compared with just over 39% at this point last year. As for RSV, only about 15% of eligible older adults have received it.

Everyone 6 months and older should get the flu vaccine. And the RSV vaccine is available to those 60 and older. Vaccination reduces the chance of infection, and, crucially, reduces the risk of progression to severe illness and death.

CNN: In addition to vaccination, what precautions should individuals be taking this holiday season?

Wen: The level of precautions people take will depend on their own medical circumstances and those of people they will be gathering with.

If someone is generally healthy, as is everyone they plan to spend time with, general precautions, such as good handwashing and staying away from others when ill, may be sufficient. For these individuals, their holiday gatherings will probably be no different compared with pre-pandemic days.

On the other hand, if someone is elderly, immunocompromised, and/or has serious underlying heart, lung, or other conditions, they may opt for additional precautions. These folks may wish to wear an N95 or equivalent mask while in indoor public spaces. When gathering with others, try to stay outdoors or, if indoors, in well-ventilated and uncrowded spaces.

If you are healthy but are going to be with those who are vulnerable, it’s advisable to speak with them to find out what precautions they would like for you to take. Perhaps they will ask that you take a rapid Covid-19 test prior to seeing them. Perhaps your loved one would prefer to socialize with you in a room with just a couple of people and not a large, loud party where there are lots of people standing shoulder to shoulder and having to shout at one another to be heard. Perhaps they will ask that everyone gathering reduces their virus exposure in the days prior to the get-together. It’s best to take the cues from the most vulnerable and most cautious people in these situations.

CNN: What should people keep in mind as they are traveling?

Wen: Again, this will depend on how careful someone is trying to be. For people who prioritize avoiding viruses, they should consider wearing a well-fitting, high-quality mask while in crowded airports and train stations. These folks should stay away from packed restaurants and bars. Consider packing home coronavirus tests when you’re on the go so you can test if you develop symptoms, or if requested by someone you are gathering with.

People traveling away from home should also have a plan should they become ill. Are they eligible for antiviral treatment, and if so, where and how will they obtain it? If they need to seek urgent medical care, where will they go? If they become symptomatic, where will they isolate? It’s better to think through all of this in advance and make sure those around you know of these plans.

CNN: What additional steps can event organizers take to help reduce the chance of viruses spreading?

Wen: People organizing holiday gatherings can make them safer by opening doors and windows to improve ventilation. For those living in parts of the country where this is possible, having an outdoor option allows those who are being more cautious the ability to attend and socialize.

Buffets can be made safer by asking people to go in small groups, not congregating around food and drink, and making hand sanitizer widely available.

If there are people attending who have expressed that they need to take extra precautions, consider asking guests to take a rapid home coronavirus test the same day as the gathering. The home test won’t find every case of COVID-19, but it does help identify those with a high viral load.

Keep in mind, though, that the coronavirus is not the only virus that can be dangerous to vulnerable individuals. This is why it’s so important that people are vaccinated to protect themselves and reduce their risk of severe disease.