Coronavirus disease (COVID-19) advice for the public:What to do to keep yourself and others safe from COVID-19?

WE'VE ALL KNOWN for a while that winter brings with it increased exposure to viruses as people begin to spend even more time indoors and colder, drier air becomes a more significant vector for airborne disease. For most of the country, picnics in the park to socialize and outdoor dining in a poorly ventilated tent will no longer be as attractive as they were during summer. New Covid-19 cases are rising in every US state. The good news is we know a lot more about SARS-CoV-2, the official name for the coronavirus that causes the Covid-19 disease, than we did back in spring. We've collected all the latest advice and gear recommendations that'll be useful to you as we head into our first winter during a pandemic, along with up-to-date information on when to expect broad vaccine rollouts. We'll continue to update this guide as new details arrive.

• Wear a Mask

Making the decision to wear a mask means you're protecting the people around you from potentially contracting the virus. And the more people who wear masks, the more effective it is for everyone. We've collected a list of the best reusable cloth face masks, even ones that fit kids better. Alternatively, you can make your own.

• Avoid Travel

Although a Harvard School of Public Health study—funded by the airline industry-backed Aviation Public Health Initiative—reported that in-cabin air filtration systems are effective enough to mitigate the risks of close passenger-to-passenger proximity, it relied on social distancing procedures during boarding and deplaning, and, crucially, it also relied on passengers wearing masks. But simply masking up on a plane doesn't eliminate all risk. Aside from the time spent on the plane, your other big concerns are the crowded airport terminals and transportation used for the last leg of your journey once you land. If you don't absolutely have to travel, don't. Put your saved money aside and plan an awesome vacation for 2021 instead.

• Vaccine News

Vaccines have arrived. But certain folks are being prioritized, so most of the population will not be eligible to get a vaccination until 2021. The Centers for Disease Control and Prevention has said there will be enough vaccines for every adult to get one next year.

Early research suggests that SARS-CoV-2 has not mutated enough to render current vaccines ineffective, but scientists say that monitoring future viral evolution will be crucial.

More than a year into the COVID-19 pandemic, public health authorities are contending with an emerging threat: new variants of the SARS-CoV-2 virus. Researchers around the world have recently identified three notable variants: B.1.1.7, first found in the United Kingdom in December; 501Y.V2, found in South Africa in December; and P1, identified in Brazil on January 13. There’s no evidence that any of these variants are deadlier than versions of the virus that came before. However, some may be more transmissible due to mutations that alter the coronavirus’s spike protein—the part of the virus that latches on to human cells, and the part that vaccines target. If left unchecked, these variants could spread faster and cause even more death and misery, on top of the more than two million confirmed COVID-19 deaths worldwide through January 15, according to Johns Hopkins University.

However, as vaccine distribution ramps up around the world, researchers are seeing early signs that existing vaccines should work with the body’s multifaceted immune system to offer some level of protection from mutated versions of the virus.

One of the benefits of the Pfizer-BioNTech and Moderna vaccines is that they can be updated quickly. But Dormitzer cautions that laboratory research and manufacturing are just two steps in a vaccine’s long, involved journey to someone’s arm. If a vaccine gets updated, government regulators would need to check whether it’s still safe and effective. Researchers say that policies governing the seasonal flu vaccine’s regular updates could provide a good framework.

“Everyone wants to take flu as the model, and I absolutely agree, flu is our model,” Dormitzer says. But “we need to figure out how we adapt the regulatory pathways—the rules of thumb—that are used for flu for this new virus.”

Crucially, researchers need to know when new variants emerge. All three experts National Geographic interviewed urged governments around the world to vastly increase their genomic sequencing of SARS-CoV-2 and to share the resulting data.“We really need to very closely monitor the sequences of the virus in patients,” Shi says. “These are the eyes and ears of our public health.”

Over the past year, as the health authorities have tried to curb the Covid-19 pandemic, researchers have trained their scientific attention on a variety of potentially risky environments: places where large groups of people gather and the novel coronavirus has ample opportunity to spread.

They have paid less attention to another everyday environment: the car. A typical car, of course, does not carry nearly enough people to host a traditional super-spreader event. But cars come with risks of their own; they are small, tightly sealed spaces that make social distancing impossible and trap the tiny, airborne particles, or aerosols, that can transmit the coronavirus.

In a new study, Dr. Mathai and three colleagues at Brown University — Asimanshu Das, Jeffrey Bailey and Kenneth Breuer — used computer simulations to map how virus-laden airborne particles might flow through the inside of a car. Their results, published in early January in Science Advances, suggest that opening certain windows can create air currents that could help keep both riders and drivers safe from infectious diseases like Covid-19.

Because it’s not always practical to have all the windows wide open, especially in the depths of winter, Dr. Mathai and his colleagues also modeled several other options. They found that while the most intuitive-seeming solution — having the driver and the passenger each roll down their own windows — was better than keeping all the windows closed, an even better strategy was to open the windows that are opposite each occupant. That configuration allows fresh air to flow in through the back left window and out through the front right window and helps create a barrier between the driver and the passenger.