The US Food and Drug Administration authorized Novavax's new COVID vaccine last week for people age 12 and older. It joins Moderna's and Pfizer-BioNTech's refreshed formulas, which were authorized the week earlier. 

This means that you have three new vaccines to choose from that more closely target the strain of COVID currently making people sick. The Centers for Disease Control and Prevention has already recommended the updated COVID vaccines for everyone age 6 months and up, along with an updated seasonal flu vaccine, so people may get one as soon as they hit pharmacy shelves, as long as it's been at least two months since their last COVID shot. (For people who haven't been vaccinated before, timing and number of doses varies.) 

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 -- meaning 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? What makes them different from last year's? 

COVID vaccines should be available now. To see which vaccines are in stock at your preferred pharmacy, you can search on Vaccines.gov by ZIP code, select a location and call the pharmacy. Or you can visit the pharmacy's website directly. 

All vaccines authorized by the FDA this summer -- Moderna, Pfizer and Novavax -- target a strain of virus that is a better match for the one currently circulating than the vaccine strain from last year. This is expected to provide better protection. However, there is a difference between the updated Novavax vaccine, which is a protein-based vaccine, and Moderna and Pfizer, which are mRNA vaccines. Novavax's new vaccine matches the JN.1 version of COVID; Pfizer's and Moderna's match KP.2, which is a more recent strain of the JN.1 lineage. 

How will people pay for COVID vaccines now?

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 ended in August due to lack of funding. While new measures will be needed to make COVID vaccines free for adults, there is a separate program in effect to keep vaccines free for all children. 

Per a CDC price sheet, the private sector cost of Pfizer's vaccine is about $137, and Moderna's is roughly $142. For adults who don't have Medicare, Medicaid or other insurance, the out-of-pocket cost for a COVID vaccine may run them up to $200 after administration fees are applied. 

Pfizer said that its patient assistance program will be available later this fall and will provide "eligible uninsured individuals" age 12 and older the vaccine for free. Moderna announced a patient assistance program last year, but didn't immediately respond to a request for comment on whether it's available.  

What should I do if I test positive for COVID?

In addition to vaccine guidance that more closely resembles annual flu shots, guidance for what to do when you're sick is more generally 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."