To date, more than 80% of people in the U.S. have received at least one dose of a vaccine against SARS-CoV-2, the virus that causes COVID-19. The original mRNA vaccines, developed by Moderna and Pfizer-BioNTech, targeted the initial strain of the virus. Since then, different variants of the virus have evolved. These included Delta in 2020 and Omicron in late 2021. Subvariants of Omicron continue to emerge. Currently, ones called BQ.1, BQ.1.1, and XBB.1.5 predominate in the U.S.
Three years into the pandemic, the immune systems of the vast majority of humans have learnt to recognize SARS-CoV-2 through vaccination, infection or, in many cases, both. But just how quickly do these types of immunity fade? New evidence suggests that ‘hybrid’ immunity, the result of both vaccination and a bout of COVID-19, can provide partial protection against reinfection for at least eight months1. It also offers greater than 95% protection against severe disease or hospitalization for between six months and a year after an infection or vaccination, according to estimates from a meta-analysis2. Immunity acquired by booster vaccination alone seems to fade somewhat faster.
Flu season is now upon us, and protecting yourself and your loved ones is still as easy as heading to the nearest pharmacy for your annual flu shot. These vaccines are formulated each year to protect against up to four circulating strains of influenza virus, and they generally do a good job. What they can’t do is prevent future outbreaks of more novel flu viruses that occasionally spill over from other species into humans, thereby avoiding a future influenza pandemic.
What you need to know Antivirals are medications that can help your body fight off viruses, including SARS-CoV-2, the virus that causes COVID-19. They work by preventing the virus from infecting healthy cells, which helps your immune system fight off infection. But viruses like SARS-CoV-2 can mutate, and antivirals may not be effective against viral variants. In a study supported by several NIH Institutes and Centers, researchers used an animal model to identify a drug that can stop SARS-CoV-2 from entering healthy cells in a way that viral variants won’t be able to evade. If it is safe and effective for humans, it may become another powerful tool in the fight against COVID-19, especially as new viral variants arise.
As colder temperatures settle in and people spend more time gathered indoors, cases of COVID-19 and other respiratory illnesses almost certainly will rise. That’s why, along with scheduling your annual flu shot, it’s now recommended that those age 5 and up should get an updated COVID-19 booster shot [1,2]. Not only will these new boosters guard against the original strain of the coronavirus that started the pandemic, they will heighten your immunity to the Omicron variant and several of the subvariants that continue to circulate in the U.S. with devastating effects.
IMPORTANCE Severeacuterespiratorysyndromecoronavirus2(SARS-CoV-2),theetiologyof coronavirus disease 2019 (COVID-19), is readily transmitted person to person. Optimal control of COVID-19 depends on directing resources and health messaging to mitigation efforts that are most likely to prevent transmission, but the relative importance of such measures has been disputed.