As a summer wave of Covid-19 hits the US, questions about vaccines, quarantine and testing are back

Moderna and Pfizer are both working on updated Covid-19 vaccines targeted to the XBB strains — subvariants of the Omicron variant. Pfizer has said its new shot could be approved in November, and vaccines are expected to be available in late September or early October.

Dr. Peter Chin-Hong, an infectious disease specialist at the University of California San Francisco, says If you are over the age of 65 or have a weakened immune system, and you have no recent immunity to Covid-19, you should not wait to get an updated Covid-19 shot. The bivalent booster currently being offered will provide sufficient immunity. People who get the existing booster will then need to wait weeks or months before getting the updated booster expected to be released in the fall.

“I would probably go and get it right now if you haven’t been boosted recently,” he says, adding that immunity to any Covid-19 strain puts older adults and the immunocompromised at an advantage over the virus.

The same applies to children who have never been vaccinated or who have not been vaccinated recently, according to Dr. Adam Ratner, a pediatric infectious diseases specialist at New York University and a member of the Committee on Infectious Diseases at the American Academy of Pediatrics.

“I would not wait if I had an unvaccinated kid,” Ratner says. “The variants that are circulating right now are less efficiently neutralized by antibodies that come from the original vaccine, but that’s not the same as there being no protection from the earlier versions of the vaccine.”

Meanwhile, most Americans who have some immunity to Covid-19 – whether through vaccination or prior infection — can likely wait until the updated Covid-19 vaccine becomes available in the fall.

When it is available, Chin-Hong says people should start to get the newest Covid-19 booster – along with their flu shot – every fall to prevent hospitalizations and death along with serious disruptions to daily life.

Has Covid isolation guidance changed?

In addition to vaccination, the best way to prevent the spread of Covid-19 is by isolating if you are sick. The CDC’s recommendation remains the same: Stay home for at least five days if you test positive for the virus.

Isolating is especially important as children across the country head back to school, Ratner says, adding that kids should stay home for a full five days if they test positive for Covid-19 and only go back to class after that if they are feeling better. Even then, children should continue to wear a mask for another five days to prevent spreading in schools.

That recommendation also applies to adults, Ratner says.

Even if they don’t have symptoms, Chin-Hong says Covid-19 patients need to use a mask. It doesn’t hurt to carry around a mask in your pocket should you need it, he says.

“As an infectious disease doctor, the best use of the mask is if you’re sick and especially if you have symptoms and putting it on to protect other people,” Chin-Hong says.

Do at-home tests still work?

It may have been a while since you have bought an at-home Covid-19 test kit, but Chin-Hong recommends that people use them if they feel ill. Don’t assume it is the flu or the common cold.

“Knowing you have [Covid-19] is important,” he says highlighting that the earlier you know you are sick the sooner you can isolate and take advantage of treatments like Paxlovid.

Knowing you are Covid-19 positive and preventing infection is also the polite thing to do, Chin-Wong says adding that it’s important to have “humility for people who are trying to protect themselves,” because people are still suffering from severe cases of Covid-19.

“The same virus may mean very little to your average person in terms of symptoms,” he says. “It may have a [larger] impact on some people in the community.”

If you are worried about your test kit being too old, Chin-Hong says don’t throw it out.

“Each kit has an expiration date, but the manufacturers keep on extending the expiration date. So, if in doubt, I would just look at the expiration date and if it’s beyond the expiration date, just go online, or call the manufacturer and ask them if they’ve extended that lot,” he says.

However, if you have a test kit from very early in the pandemic, 2020 or 2021, it may not give an accurate reading, Chin-Hong says.

What treatments work against Covid-19?

Many people who contract Covid-19 experience flu-like symptoms such as fever, cough, and headache, while others experience no symptoms at all. In these cases, the treatment plan remains the same as it has throughout the pandemic. Patients should take over-the-counter medication, rest and drink plenty of fluids.

However, with a Covid-19 case that may grow more serious, Paxlovid and remdesivir are available — and may be underutilized, Chin-Hong said.

Remdesivir is an antiviral medication that is often used to treat more serious cases of Covid-19, but Chin-Hong adds that administering that medication is not simple. The drug does not have many interactions, but it needs to be given via an IV over the course of three consecutive days.

“[That is] a limitation for people in the outpatient setting or who don’t have access to a health care system that has an infusion center,” he says.

Paxlovid is also an antiviral medication that is a combination of two medications – nirmatrelvir and ritonavir – which are taken together as pills for five days within the first five days of a person’s Covid-19 symptoms.

A study published earlier this year in Lancet Infectious Diseases shows Paxlovid was 80% effective in preventing hospitalization or death if a Covid-19 positive patient started taking the drug within five days of symptom onset.

Chin-Hong says he recommends that Paxlovid be prescribed to all Covid-19 patients who are older or have a weakened immune system. However, a study published in JAMA last month suggests uptake isn’t that strong. In the study, researchers found that only 25% of nursing home residents were prescribed Paxlovid between May 2021 and December 2022, despite the high risk of Covid-19 infection and complications.

Despite its effectiveness, there are downsides to the medication. Paxlovid is known to interact with many other drugs, which Chin-Hong points out may be the reason why it is not being used for mild to moderate cases of Covid-19.

“I think that’s probably the biggest question and the biggest variability in terms of how clinicians see it,” he says. “Some clinicians are very comfortable with managing drug interactions; other clinicians don’t know or are afraid to use it.”