Johnson & Johnson Vaccine Far Less Effective Against Delta Variant, Study Suggests

A study from a team of New York University researchers found the one-shot Johnson & Johnson vaccine is far less effective at preventing coronavirus infections from the Delta variant and other mutated forms of the virus than from earlier strains, a concerning find since the Delta variant now accounts for almost all U.S. Covid-19 cases.

KEY FACTS

The study, which has not been peer reviewed, was based on tests conducted on blood samples drawn from people who have received the three coronavirus vaccines approved for use in the U.S.

According to the New York Times, the findings are consistent with earlier reviews of the similar AstraZeneca vaccine’s performance against the Delta variant, which found around a 33% efficacy rate.

Clinical trials put the J&J vaccine’s efficacy at around 66% against the original coronavirus strain, while the two-shot Pfizer and Moderna vaccines were more than 90% effective.

CDC Director Dr. Rochelle Walensky said Tuesday the Delta variant now makes up around 83% of all Covid cases in the United States.

The findings from the NYU studies contradict earlier, smaller studies published by Johnson & Johnson, which suggested the vaccine was effective against Delta and other new variants.

WHAT TO WATCH FOR

The study’s authors suggested J&J recipients might require booster shots for better protection against the Delta variant, but public health officials are not recommending boosters for any vaccines at this time.

BIG NUMBER

More than 13 million. That’s how many Americans received the single-dose Johnson & Johnson shot, according to the CDC. The number actually represents just a small slice of around 161.5 million Americans who have been fully vaccinated.

KEY BACKGROUND

Rising cases, hospitalizations and deaths across the U.S. are fueling concerns about another major Covid spike. Numerous cities and localities are now urging all residents to wear masks in public again, even if they’ve been fully vaccinated, while a stock market plunge on Monday was largely attributed to worries over the Delta variant. The vast majority of those impacted have not been vaccinated, though, leading Walensky to say last week: “This is becoming a pandemic of the unvaccinated.”

TANGENT

The Johnson & Johnson vaccine has had several reports of problems since it received approval in February. In April, the federal government recommended a 10-day pause on Johnson & Johnson vaccinations while it investigated links to a serious blood clotting issue. Another problem came up earlier this month, when it was reported the vaccine could raise the risk of a neurological disorder called Guillain–Barre syndrome. Instances of both Guillain–Barre syndrome and blood clotting after the J&J vaccine have been extremely rare, but the issues have been enough to lower public confidence in the vaccine compared to the other shots available in the United States.

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