It’s been more than 300 days since Chinese officials first told the World Health Organization that people were sick with an unknown virus in Wuhan. Scientists quickly learned what the virus was (a coronavirus) and what it did (make people sick with a disease called COVID-19), and it spread like wildfire around the globe. Over 1 million people around the world have died, hundreds of thousands get sick every day, and the United States has the distinction of the worst outbreak in the world. 

When we published our first guide to the coronavirus, researchers still weren’t sure how the virus spread, when people were contagious, or if you could catch it twice. There’s still some lingering uncertainty around some of those questions, but scientists have made some remarkable progress toward answers. 

Doctors now have a better sense of which treatments work (and which don’t) and are better at caring for patients. Public health organizations analyzed data coming in and issued and reissued guidelines as new information became available. Both treatments and guidelines may change even more as the pandemic continues, although not as quickly as they did in March and April. The Verge has been following all of those updates, and we’ll continue to do so as the months go on.

For now, here’s a COVID-19 cheat sheet, breaking down public health recommendations and knowledge that you might need to navigate this ongoing pandemic.

This page may be updated with new information as recommendations change.

How can I protect myself from COVID-19?

The coronavirus that causes COVID-19, SARS-CoV-2, is highly contagious, and if you’re in contact with someone who is infected, you’re at risk of catching at as well. The best ways to protect yourself, then, are to stay away from people who have COVID-19. But some infected people don’t have symptoms — without testing, you can’t say for sure that someone doesn’t have the virus. Anyone who’s infected can release tiny virus-laden particles from their mouth or nose when they cough, talk, or breathe. Staying far away from others, even if they don’t look sick, can help keep you safe. 

Early recommendations were to stay around six feet apart from people you don’t live with. In some situations, that still makes sense. That yardstick doesn’t work in all situations, though. Sometimes, virus-laden particles can travel farther than that. They can also linger in the air, especially indoors and in places that have bad ventilation. That’s why you should avoid being in crowded indoor spaces. Even if you’re six feet apart from someone inside, they could exhale clouds of virus that could collect in the air and make their way to you.

You should also wash your hands regularly and wipe down surfaces like doorknobs and countertops, although the virus doesn’t seem to spread as easily that way. 

Do cloth masks actually do anything?

Face masks do two things: keep you from accidentally spreading the coronavirus to others and cut down on your risk of catching COVID-19. If you’re infected and don’t know it, wearing a mask will block some of the viral particles you exhale with every breath — which means less makes their way into the eyes, noses, and mouths of the people around you. 

Some research shows they can also stop you from getting sick. The gold-standard masks for health care workers, N95 masks, filter out up to 95 percent of incoming contaminants and particles, which could carry viruses. They help protect doctors and nurses who are in close contact with COVID-19 patients. But there is some evidence that even simple cloth masks can filter the air you breathe in, reducing the amount of virus you might be exposed to. Some research shows that if you’re hit with a lower dose of the virus, you won’t get as sick even if you do contract COVID-19. Models by epidemiologists also show that tens of thousands of deaths could be prevented if everyone wore masks all the time.

What are the symptoms of COVID-19?

Symptoms include fever, cough, difficulty breathing, body aches, headaches, and loss of taste or smell. They’re similar to the symptoms of the flu — which makes it hard to tell the two apart without testing. 

When should I get tested?

The Centers for Disease Control and Prevention says that anyone who has any symptoms of COVID-19 or who has spent time with someone who is sick should get tested for the virus. You may also want to get tested if you’ve spent time in a higher risk environment. The New York City Department of Health and Mental Hygiene, for example, recommends that anyone who has been in a large indoor gathering should get tested. If you live in an area with a lot of COVID-19 or if you’ve recently traveled to a place with widespread transmission, you may also want to get tested more regularly. 

What does the test tell me?

A test tells you if there was coronavirus in your body at the exact moment the swab touched the inside of your nose or the back of your throat. That’s important information, especially if you’re feeling sick. A negative test result, though, is not a free pass to do anything you want — especially if you’ve been exposed to someone who tested positive or were in a crowded area. It can take up to two weeks for an infection to show up, and you could test negative one day and positive the next. 

How long am I contagious? 

The amount of virus floating around in the body of a person with COVID-19 tends to jump up a day or two before they start to feel sick and then gradually decline. Your viral levels aren’t an exact marker for how contagious you are, but it’s used as a proxy. Some research shows that most people pass the virus to others either at some point in the 48 hours before symptoms start or within the 10 days after. The CDC recommends that people stay isolated for at least 10 days after symptoms start and until they go 24 hours without a fever.

How sick will I get if I catch it?

That depends on how old you are and if you have another health problem. As you get older, your risk of a severe case of COVID-19 goes up — in part because your immune system is weaker. People who have conditions like diabetes or high blood pressure are also at higher risk of developing complications from the disease. 

People who are young and healthy, though, can still get very sick. Just because something is rare doesn’t mean it never happens, and the disease can be dangerous for everyone. Some people who catch the disease have symptoms for months. These patients, called “long-haulers,” end up chronically ill. It’s still not clear why some people experience those long-term effects. 

How will I be treated if I get sick? 

That depends on how sick you are. If you’re sick but not sick enough to need to be in the hospital, there isn’t much doctors can do. You can take over-the-counter medication, drink fluids, and should monitor your symptoms for signs you’re getting worse. 

Doctors have gotten much better at treating hospitalized COVID-19 patients since this disease emerged. Studies found that drugs like the steroid dexamethasone improve the survival rate for patients with serious symptoms. They aren’t put on ventilators as often as they were earlier in the pandemic. Instead, they’re flipped onto their stomachs, which helps them take in more oxygen. 

Depending on how clinical trials go, we might have a new category of treatment — synthetic antibodies — at some point in the future. Those drugs work by blocking the virus, and they’re being tested in non-hospitalized patients. Even if they work, though, they’ll be available in very limited quantities, and most people won’t be able to get them. 

If I get sick and then get better, am I immune?

Most experts think that most people who get COVID-19 and recover are protected against the virus for at least a short period of time, although it’s not clear how long that stretch is. That isn’t the case for everyone, though. There have been a handful of reports of people who got sick, recovered, and then caught the virus again only a few months later. Those people are probably the exception, rather than the rule — but they show that people who’ve been sick shouldn’t assume they can just go about their normal lives and not worry about the pandemic. 

Can I get the flu and COVID-19 at the same time?

You could theoretically get hit with both COVID-19 and the flu at once — which is one reason why it’s so important to get a flu shot. There isn’t much research on what happens when people get both illnesses, but a small study in the United Kingdom found that it significantly increases risk of death.

When will a vaccine be ready? 

By November or December, we should have initial data from the clinical trials of a few vaccine candidates. If the trials show that the vaccines work to either prevent people from catching COVID-19 or to make the disease milder if they do catch it, the Food and Drug Administration could authorize it for emergency use. If that happens, a company could start distributing a vaccine. There’d be very limited doses, though, and the first shots would go to the people at the highest risk — in most places, probably health care workers, first responders, and the elderly. 

So a vaccine might be “ready” by the end of 2020 or early in 2021, but that doesn’t mean you’ll be able to get one. More than one vaccine will probably get authorized over the next year or so, and distribution will be a major challenge. 

When will this be over? 

No one knows. Experts do know, though, that it won’t last forever. Pandemic viruses eventually stop being pandemics and transition into a normal disease we deal with on a regular basis. As we learn more about COVID-19 and develop better tools to prevent and treat it, the coronavirus will become less of a threat. That probably won’t happen for months — cases are still spiking in the US and around the world — but at some point, the virus won’t be as scary anymore. Until then, it is a real threat to everyone. Taking it seriously is the best way to help the end come more quickly.