If the U.S. government had done a better job making rapid Covid-19 tests available, the advice for how to use them this holiday weekend would be easy: Take one at the start of every day when you planned to spend time with people outside your household.
That approach is possible in other countries. In Britain, pharmacies offer free packs of seven tests that people can take at home. In Germany, rapid tests are also widely available and mostly free. In this country, the situation is different, largely because the F.D.A. has been slow to approve the tests.
The Biden administration has not been as aggressive in fixing the situation as it could have been, but it has made progress. A couple of months ago, tests were often impossible to find. Now, they are sporadically available at many stores. Friends and family around the country have told me this week that they have usually been able to find a test after looking in enough places.
The tests are not free, however. They typically cost about $25 for a pack of two. The combination of their cost and irregular availability means that Americans interested in rapid tests often must make choices about when to use them.
Today’s newsletter offers a guide for doing so, especially as a way to protect older people — who remain the most vulnerable to serious Covid illness — during Thanksgiving weekend.
“Rapid tests can help reduce worries about gathering with loved ones for the holidays,” Jennifer Nuzzo, an epidemiologist at Johns Hopkins University, told me. Nuzzo’s immediate family plans to take tests on Thanksgiving, before going over to their hosts for the meal. So do I.
The Covid tests that you take in a doctor’s office or testing center are usually PCR tests, which are designed to identify whether you have any amount of the Covid virus. They can sometimes come back positive even if you had the virus weeks earlier and have not been infectious for a long time.
The rapid tests — also known as antigen tests — are designed to tell whether you are infectious. That’s why they are such a powerful public-health tool. They can prevent somebody with the virus from spreading it to others.
“For too long, people thought of testing as an extra and not the core, and it needs to be thought of as the core,” Mara Aspinall, a professor at Arizona State University and former biotechnology executive, told Kaiser Health News.
The most widely available antigen test seems to be BinaxNOW, from Abbott. You should also feel comfortable using QuickVue, Ellume and Flowflex, among others. If you search for one of these tests online and a website points you to a different brand, do some research. Others can be very expensive.
Both CVS and Walgreens have search engines that let you find tests for sale near you. I recommend calling the store to confirm it still has them in stock — and then immediately going to buy it. A store may limit you to buying one test pack at a time.
Some people find the tests easy to conduct. Others have told me that the process is tricky — more so, for example, than taking a home pregnancy test. Either way, set aside time to read the directions and watch the how-to video.
“It is critically important that you carefully read any instructions for the type of test you are taking, and follow them to the letter,” Dr. Karl Laskowski, who helps oversee Covid testing at Brigham and Women’s Hospital, told Julia Taliesin of Boston.com.
You will usually get a result within 15 minutes. Keep in mind that both false negatives and false positives are possible. Antigen tests typically identify 98 percent of infectious cases, according to Dr. Michael Mina, a Harvard University epidemiologist.
If you get a positive result, take it seriously, and quarantine yourself until you know more. Ideally, you would try to confirm the result with a PCR test or a second rapid test — from a different brand, my colleague Tara Parker-Pope says. If the second is negative and you are vaccinated, you can probably trust the negative.
Because most Americans have limited access to rapid tests, they need to triage their use. The two most important times to take a test are either after you may have been exposed to the virus or before you are spending time with medically vulnerable people, like those in their 70s or older.
“I try to tell people it’s a snapshot good for one day only,” Tara told me. “And that you need to keep testing if you think you were exposed to Covid or if you have been traveling through airports or on trains.”
If you are attending multiple gatherings this weekend and do not have enough tests, focus your testing on the days when you are seeing anybody vulnerable. For most people, the vaccines have turned Covid into a manageable disease — one that is highly unlikely to lead to severe illness and not so different from other respiratory illnesses. But for many older people, Covid remains a meaningful threat.
Not everybody in your household has the same chance of Covid exposure. With a limited number of tests available, it can make sense to focus on people who have the highest likelihood of having been infected — and, by extension, infecting others.
Nuzzo suggests prioritizing two groups for rapid testing: people who are not fully vaccinated, like children; and those who have spent more time in settings where they might have been exposed.
Even with the limitations of rapid testing in the U.S., the tests can play an important role in slowing the spread of the virus. And the situation does seem to be improving. The F.D.A. approved three more tests this week, and the Biden administration continues to spend more to expand their availability.
By Christmas and New Year, tests should be easier to find than they are this week.
Related: See where cases and hospitalizations are surging in the U.S.
Who’s up for a Grammy?
It’s that time of year: Grammy nominations. The 64th annual awards show will be held in Los Angeles in January.
First, a surprise: Jon Batiste, a composer who is also the musical director on “The Late Show With Stephen Colbert,” scored the most nominations — 11. Justin Bieber, Doja Cat and H.E.R. followed with eight apiece, while the pop stars Billie Eilish and Olivia Rodrigo earned seven. “It’s a reminder that the presumed and actual audiences for the awards show and the network both skew old,” the music critic Jon Caramanica writes. “Perhaps only in this echo chamber, Batiste qualifies as a pop star.”
Another twist: Abba scored its first Grammy nomination, for the group’s comeback single “I Still Have Faith in You.” “That’s obviously one of the Grammys’ better-late-than-never nominations,” the music critic Jon Pareles wrote.
The ceremony has also overhauled its nomination process — for years, artists, including Jay-Z and the Weeknd, have slammed the Grammys for passing over Black artists in top categories. “The effect seems less dramatic than many expected,” Ben Sisario writes. “This year, the distribution of Grammy nods has followed a familiar pattern of mixing pop superstars with heroes of the old guard.”
The pangram from yesterday’s Spelling Bee was fixated. Here is today’s puzzle — or you can play online.