Nuzzo: These days I recommend that people use rapid tests because lab-based tests have been so unpredictable in terms of when you will get test results back, especially before the holidays because of demand. While the performance of rapid tests is improved through repeated testing, even a perfect test is only an assessment of your status at the time the test was performed. So it is most important that you test on the day of the gathering. But you can also test a couple of days before to improve the reliability of your test results.
Morrison: Even though the vaccines are highly efficacious, a subset of fully vaccinated people will get infected and develop Covid-19. The good news is that the majority of breakthrough cases are mild and resolve more quickly in vaccinated people because their immune system is set to respond quickly and clear the virus faster. In my social circle, everyone is vaccinated (except for those who cannot be), and we mask indoors and in crowded areas so we are at very low risk to contract the virus. Before we gather as a group, anyone who has potentially been exposed to SARS-CoV-2 takes a rapid test a day or two before the event. If they test positive, they stay home.
Is another variant coming?
How much concern should there be about a new, more dangerous variant, given that most of the undeveloped world is being neglected and a sizable proportion of U.S. citizens have not been vaccinated yet? — Michael James Wilson, Pennington, N.J.
Nuzzo: It’s a real and reasonable concern. Improving access to and uptake of first and second vaccine doses is essential for ending our worries about this pandemic. Aside from being in our pragmatic best interest, it’s also the morally right thing to do, as increasing the number of people who are vaccinated helps to limit the number of preventable deaths that this virus will cause.
Morrison: Viruses can only mutate when they replicate, and they can only replicate inside cells — unlike microbes such as fungi and bacteria. As such, if there are unvaccinated people in which SARS-CoV-2 can replicate, this virus will continue to acquire new mutations. It’s not a matter of if, but instead when, a new variant will arise. That’s why we need to stop transmission in its tracks. We are currently failing to do so. Less than 5 percent of the people in low-income countries have received at least one vaccine dose. We need to vaccinate the whole globe if we are to prevent the emergence of new variants. It is the moral and scientifically sound thing to do.
Are better times coming?
What would be a low estimate of infections going into the winter? Is there any good news on the horizon? — Veronica Hansen, Bellingham, Wash.
Marr: The number of new cases has leveled off, and with winter and holiday travel and gatherings coming, I fear that we may be stuck at this stage for a couple of months. The good news is that kids ages 5 to 11 can now get vaccinated. That will not only help protect them, but it will also help reduce community spread of the virus. That said, the trajectory of the pandemic has been hard to predict, so we need to be prepared for the unexpected.