Pointing to a handful of new studies, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said in a recent briefing that after both doses, the mRNA vaccine from Pfizer-BioNTech is approx. 80 percent effective in preventing infection from the delta. variant, 88 percent effective in preventing symptomatic disease and 96 percent effective in preventing hospitalization caused by delta. However, new data from Israel show lower levels of efficacy ̵
However, the key to this protection is full vaccination, Pekosz says. “If you have only received one of your mRNA shots, this is where you can really see the delta variant being able to evade some of these immune responses,” he says. In fact, it turned out that a dose of two-dose mRNA vaccines was only 33 percent effective in preventing symptomatic disease caused by the delta variant in a preprint study out of the UK
“So if you have a good strong immune response generated by both doses of the mRNA vaccine, you need to be in a good place,” says Pekosz. “But if you are only partially immune – if you are in between doses, or if you are taking the first dose and you decide to skip the second dose – then you are in an area where the vaccine can protect you against older strains, but it may not be enough immunity to protect you from the delta variant. ”
Johnson & Johnson released a statement on July 1, noting that its one-shot vaccine “generated strong, sustained activity against the rapidly spreading delta variant and other widespread SARS-CoV-2 viral variants.” The studies containing this data are currently being sent for publication. Hours before J & J’s announcement, Fauci said it is reasonable to assume that the effectiveness of J & J’s vaccine is on a par with AstraZeneca’s vaccine, which uses the same viral vector technology. The AstraZeneca vaccine, which is not approved for use in the United States, has been shown to be 60 percent effective in preventing infection and 92 percent effective in preventing hospitalization caused by the delta variant.
Experts will keep an eye on the strength and duration of these vaccines – especially in more vulnerable populations. Pekosz does not see the need for a national booster campaign yet, but says it is not out of the question that “highly vulnerable populations may be asked to go in and take a booster consisting of the delta variant or perhaps the next variant that comes off, just to make sure they maintain that level of immunity. ”
5. It may be a good idea to keep the mask practical
Fully vaccinated individuals no longer need to wear a mask in most situations, according to CDC guidelines issued in mid-May. But experts say you may want a practical one – especially with delta on tear.
The reason? No vaccine is 100 percent effective in preventing infection or disease, and with a highly contagious virus gaining traction in a number of communities across the country, a little extra caution makes sense, says Pekosz: “If you know you are in a situation where you come in contact with people who may be carrying the virus, it is always best to have another layer of protection, such as a mask or some level of social distance. ”
Los Angeles County recently recommended that its residents, regardless of vaccination status, wear masks in indoor public spaces “until we better understand how and to whom the delta variant spreads.” The area has seen an increase in new COVID-19 cases, probably due to delta.
Timothy Brewer, MD, professor of medicine and epidemiology at the University of California, Los Angeles (UCLA), says there is no good evidence to suggest that vaccinated individuals need to wear masks when outside, but it is “probably reasonable to consider wearing a mask when you are indoors and around many other people, especially if you cannot physically distance yourself.” He still wears a mask in the grocery store and says he would do the same if he was going to a big indoor event “like a concert or a movie theater.”
It is unclear whether other communities will follow LA County and issue new mask guidelines. In the meantime, experts say, be aware of what is happening in your area. If vaccination rates are high where you are, there is less risk. “The more you are exposed to people who are not vaccinated, the greater the chance of becoming infected,” says El-Sadr.
Also, keep this in mind when traveling this summer – especially considering that more than a third of U.S. counties have vaccination rates below 30 percent, according to CDC data.
“If the risk increases, why not do something to reduce the risk? Wearing a mask is an easy” solution, says Pekosz.