Delta variant: Moderna & Pfizer doses effective, jury out on Johnson & Johnson vax

Rocky Mountain Regional VA Medical Center investigational pharmacy technician Sara Berech is reflected in the glass of a fume hood as she prepares a dose of the Johnson & Johnson COVID-19 vaccine for a clinical trial on December 15, 2020 in Aurora, Colorado.
Rocky Mountain Regional VA Medical Center investigational pharmacy technician Sara Berech is reflected in the glass of a fume hood as she prepares a dose of the Johnson & Johnson COVID-19 vaccine for a clinical trial on December 15, 2020 in Aurora, Colorado. Photo credit Michael Ciaglo/Getty Images

It might feel like the coronavirus pandemic is winding down.

But there are major concerns for parts of the U.S. where a large number of people have not been vaccinated for COVID-19. That is because the Delta variant – first identified in India – is spreading quickly.

Some expect it to become the dominant strain in America by the end of summer because it seems to be better at infecting people who have not been vaccinated. The Delta variant represents about 10% of U.S. cases today.

But if you are fully vaccinated – that’s two weeks clear of having both shots of the two-dose course of Pfizer or Moderna or the single-dose Johnson & Johnson – we’re told you should be fine.

"If you are a fully vaccinated person, especially with the Moderna and Pfizer vaccines, the Delta variant really poses no risk to you," said Dr. Amesh Adalja Senior Scholar at the Johns Hopkins Center for Health Security. "The Johnson & Johnson vaccine likely is effective at stopping what matters when it comes to the Delta variant: serious disease, hospitalization and death. We’re going to get more data on the Johnson & Johnson vaccine soon, but I think the bottom line message with the Delta variant is that this problem can be completely solved by having vaccination rates as high as possible."

In the U.K., they are seeing breakthrough cases in fully vaccinated people but most people there got the AstraZeneca shots – not approved for use here in the U.S. The Johnson & Johnson shot uses a similar technology to AstraZeneca but also has key differences to do with how it works with the spike protein so the guess is that it will do better, according to Dr. Adalja.

"The early data that we’re seeing shows that the Johnson & Johnson vaccine does work well," he added.

He told KCBS Radio it’ll become more important to watch out for how these vaccines do at protecting against serious cases of COVID-19 that will put you in a hospital. He’s less concerned about breakthrough cases that don’t make people very sick.