The US-based pharmaceutical Johnson and Johnson said on Thursday that its one-shot vaccine is effective in controlling the delta variant of COVID -19.

The company cited the lab tests of the vaccine recipients' blood. And amid concern that their shot might require a booster, the company said its immune response lasts eight months and counting.

“We believe that our vaccine offers durable protection against COVID-19 and elicits neutralizing activity against the Delta variant,” Paul Stoffels, chief scientific officer at Johnson & Johnson, said in a news release. “This adds to the robust body of clinical data supporting our single-shot vaccine’s ability to protect against multiple variants of concern.”

Although the vaccine's proven efficacy against the so-called Indian variant is good news, the variant still poses a great risk in the region where the vaccination is sparse.

There have been reports of a very small number of dangerous blood clots occurring in people who received the Johnson & Johnson vaccine, which led the United States to briefly pause its rollout in April. Following a safety review, the CDC and the FDA lifted the suspension.