Abooster of Johnson & Johnson's (J&J) one-shot coronavirus vaccine offers a stronger immune response months after people receive their first dose, the company said Tuesday.

In a statement, J&J said an extra dose either two months or six months after the initial shot increased defense against the virus. The results, however, have not yet been peer reviewed or published, the Associated Press reported.

In the midst of a delta variant surge, a new study finds that giving a booster dose of the Johnson & Johnson shot six months after primary vaccination results in a nine-fold increase of a crucial antibody response, according to a company press release.

Meanwhile, a prior study found that people vaccinated with the Johnson & Johnson vaccine still had a durable immune response at least eight months later, even without a booster.

The U.S. Food and Drug Administration on Monday added a warning to the fact sheet for Johnson & Johnson's (JNJ.N) COVID-19 vaccine saying that data suggests there is an increased risk of a rare neurological disorder in the six weeks after inoculation.

The Johnson & Johnson vaccine will soon have a new warning from the Food and Drug Administration after the shot was linked to a rare but serious side effect in a handful of patients, it was revealed Monday. 

The side effect, Guillain-Barré syndrome — a condition that occurs when the immune system attacks the body’s nerves — has been detected in about 100 people after 12.8 million jabs of the single-dose shot were administered, the Centers for Disease Control and Prevention told the Washington Post. 

The US Food and Drug Administration updated the label on Johnson & Johnson's coronavirus vaccine Monday to warn of the possible increased risk of a rare neurological complication known as Guillain-Barré syndrome.

While the FDA said it had not established the vaccine could cause the syndrome, it noted an increase in reports of the sometimes paralyzing condition.

The delta variant is already the most dominant strain of the virus in some U.S. states, and that’s putting some Americans easing back into “normal” life on edge.

This variant, which was first identified in India in December, now makes up nearly half of COVID-19 cases in some regions and one-quarter of cases in the U.S., based on virus samples that have been sequenced, according to remarks made Thursday by Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention.

The Food and Drug Administration said Friday that it's allowing for the release of two batches of the Johnson & Johnson COVID-19 vaccine made at the Emergent BioSolutions facility in Baltimore, where 100 million doses had been set aside for review after an accidental contamination.

Why it matters: The two authorized batches amount to approximately 10 million doses of J&J's single-shot vaccine, according to AP. The doses could end up being used in the U.S. or exported to other countries.

About 3 in 4 unvaccinated adult Americans are unwilling to get the Johnson & Johnson coronavirus vaccine, a Washington Post-ABC News poll out Monday indicates.

Why it matters: Less than half of all U.S. adults polled said they thought the J&J shot — which presents fewer logistical challenges than the more temperature-controlled, two-shot Pfizer and Moderna vaccines — is safe.

A federal vaccine advisory committee is reconvening Friday to discuss next steps for Johnson & Johnson’s coronavirus vaccine after health officials recommended last week that states pause use while six U.S. cases of a rare and severe type of blood clot were reviewed.

Advisers to the U.S. Centers for Disease Control and Prevention will meet again on Friday to consider whether it is safe to resume injections of Johnson & Johnson’s COVID-19 vaccine, as senior U.S. health officials prepare for a green light.

The panel last week called for more data about a possible link to rare blood clots in the brain before deciding how and whether to end a "pause" in administration of J&J vaccines called for by the CDC and the Food and Drug Administration.