The Delta variant, which was first identified in India, is worrisome because it is highly contagious and spreading rapidly around the globe. Unvaccinated people who are infected with Delta are twice as likely to be hospitalized as those infected with Alpha, the variant that was first detected in Britain.
What has been surprising about the Delta variant is how easily it seems to be transmitted. In Australia, security cameras documented a brief encounter of two people passing each other in a shopping mall; one of them was unknowingly infected. The shoppers were facing each other at one point and breathed each other’s air for only seconds, which led to the second person getting infected. (The transmission was confirmed through genetic sequencing.) While such a brief encounter typically wouldn’t lead to transmission, the case signaled how important it is that people get vaccinated before the Delta variant spreads further.
CDC estimates that the Delta variant now accounts for upwards of 74% of new COVID infections in the United States. But if you are among the vaccinated, most experts say you don’t need to be fearful. Studies show that two doses of the Pfizer vaccine offer 88 percent protection against the Delta variant, compared to 93 percent protection against Alpha. The Moderna vaccine has performed similarly to Pfizer in other studies, so it’s expected to give a similar level of protection against Delta. Moderna has said test-tube studies using blood samples from vaccinated people showed the vaccine is still highly effective against the Delta variant, which caused only a “modest reduction” in virus-fighting antibodies in the samples.
A recent Public Health England study found that partially vaccinated people are 75 percent less likely to be hospitalized than an infected person who isn’t vaccinated. Those who are fully vaccinated are 94 percent less likely to be hospitalized. “If you’ve had two doses of the Pfizer vaccine, like me, you should be protected against the Delta variant,” said Gregg Gonsalves, assistant professor of epidemiology at the Yale School of Public Health. “I could go maskless and feel fine about it from that perspective. I think for the U.S. — where we have states that have poor vaccination coverage and among populations who haven’t been vaccinated — the Delta variant is a problem.” Dr. Gonsalves said that even though he is fully vaccinated, he will continue to mask up in the grocery store and other public spaces as we wait for more people to get vaccinated.