J&J says booster of its vaccine provides strong increase in antibodies

Johnson & Johnson (J&J) said a booster of its Covid-19 vaccine provided a rapid and strong increase in antibodies, supporting use of a second shot among people who previously received its single-dose immunisation.

A second dose of the J&J vaccine led to a ninefold increase in Covid-fighting antibodies compared with the levels participants had 28 days after getting their first shot, the healthcare giant said on Wednesday, citing interim data from an early-stage trial. Some 230,603 doses of the vaccine have been delivered in the Republic.

Trial participants were given the booster six months after the first shot, according to J&J. Significant increases in antibody responses were seen in subjects ages 18 to 55, and among those 65 or older who were given a lower dose of the booster. The data is being submitted to a preprint medical publication MedRxiv.

The latest findings, coupled with data showing the single shot's durability for at least eight months, underscore a future booster strategy, said Mathai Mammen, the global head of research and development for J&J's pharmaceutical subsidiary Janssen.

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“We look forward to discussing with public-health officials a potential strategy for our Johnson & Johnson Covid-19 vaccine, boosting eight months or longer after the primary single-dose vaccination,” Mr Mammen said in a statement.

Health experts around the world are engaged in a debate about when Covid-19 vaccine booster shots will be needed, and who should get them first. Many countries have yet to immunise one-tenth of their population, and the World Health Organisation has called on governments to delay boosters until more are protected globally.

Waning protection

Meanwhile, the United States announced this month it will aim to start offering boosters to certain recipients of the Pfizer and Moderna vaccines starting on September 20th. Due to concerns about waning protection, fully-vaccinated adults will become eligible for the third dose eight months after completing their regimen.

The Biden administration anticipates 100 million boosters of those so-called messenger RNA vaccines would be given out by the end of 2021.

That has left recipients of J&J’s single-shot vaccine, which employs a different technology, wondering about their own protection against the virus. More than 14 million US residents have received the J&J shot, according to the Centers for Disease Control and Prevention.

Public-health and medical experts from the US department of health and human services said on August 18th that they anticipated J&J booster shots would likely be needed.

J&J said in July that that recipients of its vaccine produced strong neutralising antibodies over the course of at least eight months against all variants, including Delta. – Bloomberg