New COVID vaccines, which are better matched to target the virus, will start rolling out soon, after the US Food and Drug Administration signed off on the shots Thursday. 

The new vaccines are made by Pfizer-BioNTech and Moderna. The Centers for Disease Control and Prevention has already recommended the updated COVID vaccines for everyone ages 6 months and up, along with an updated seasonal flu vaccine, so people may get one as soon as they hit pharmacy shelves in the coming days, as long as it's been at least two months since their last shot. 

Summer 2024 has seen "very high" rates of COVID, according to wastewater data from the CDC. Part of the summer-surge problem may have to do with people's waning immunity from previous vaccines and infections (along with the ever-revolving door of new and contagious versions of omicron). So the availability of updated vaccines is expected to be a useful tool to stave off severe illnesses as we head into cooler months and respiratory virus season.

As COVID has moved from pandemic to endemic (this means COVID is still making people sick, but in more-predictable ways that can be mitigated by available treatments), officials at the CDC have streamlined guidance around vaccines and isolation to make it easier for everyone to follow when they have symptoms of a respiratory virus. Here's what to know.

When will the new COVID vaccines be available? How much do they cost?

Most likely in the coming days. The CDC preemptively recommended shots from Moderna, Pfizer and Novavax earlier this summer, and now that vaccines from Moderna and Pfizer are officially approved by the FDA, it's just a matter of when pharmacies receive them. The updated vaccines from both mRNA companies target KP.2, which, compared with the strain targeted by last year's shots, more closely resemble the versions of the virus that's currently making people sick.

The FDA hasn't yet signed off on Novavax's new shot, but it's expected to be another option later this year.

One change this time around is that the cost of COVID vaccines is no longer being covered by the federal government, though both COVID and flu vaccines should be covered by people's insurance, including Medicare. The Bridge Access Program provided COVID vaccines for free to people without health insurance, though it's slated to end this month. While new measures will be needed to keep COVID vaccines free for adults, there is a separate program in effect to keep vaccines free for all children. 

What should I do if I test positive for COVID?

The CDC's new general guidance is focused on what to do while you have symptoms of a respiratory virus or feel sick, rather than on the results of a COVID test. But because treatment depends on which virus you have, it's always best to take a COVID test if you're able to do so. 

If you're at a higher risk of any respiratory virus -- which includes complications from COVID, flu or RSV -- it's especially important to find out which virus you have (through testing and seeking medical care) so you can get the right treatment, as it varies depending on which virus you're sick with.

If you're an adult in your 50s and up, or if you have a chronic condition like heart disease, high blood pressure, asthma, diabetes or something else, you're likely eligible for an antiviral medication (including Paxlovid) that will lessen the severity of the disease and reduce your risk of hospitalization. You can get it by calling your regular primary care doctor or pharmacist or by finding a Test to Treat center, where people who have Medicare or Medicaid, uninsured people and those with VA insurance or those who are receiving Indian Health Services can get free COVID-19 testing and treatment. It's important that you start taking the antiviral within the first few days of symptoms for the medication to work. 

For everyone who has COVID, or suspects they might, the CDC says to follow its general guidance for preventing the spread of respiratory viruses when you're sick. This includes staying home and away from others when you feel sick, whether or not you test.

You can "go back to your normal activities," the CDC says, as long as it's been 24 hours since your symptoms started improving overall and as long as it's been 24 hours since you've had a fever (and you haven't taken fever-reducing medicine, like ibuprofen). Then, take additional precautions for five days after you improve, which may include wearing a mask or avoiding people who are at higher risk of severe illness from COVID or other respiratory viruses.

This is a change from pandemic-era guidelines that were more specific about when and how long to isolate after an exposure to COVID-19 or a positive test result. Why is that? 

"This is an endemic virus for which there is a lot of population immunity and medical countermeasures," Dr. Amesh Adalja, an infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security, said in an email. "Guidance has to reflect that context and be such that people can employ it with relative ease."