The Pentagon on Wednesday announced mandatory Pfizer vaccinations, calling it "necessary to protect the safety of our service members and force."

Pentagon press secretary John Kirby said 68% of the active duty force is fully vaccinated and just over 76% have had at least one dose.

Pfizer's COVID-19 vaccine was granted full approval by the FDA on Monday.

-ABC News' Luis Martinez

Delta is raising health insurance premiums for unvaccinated employees by $200 a month to cover COVID-19 costs like potential hospitalization, which the airline says has cost it $40,000 per person on average.

In recent weeks, all Delta employees hospitalized with COVID-19 were not fully vaccinated, Delta CEO Ed Bastian wrote in a memo to employees.

Currently 75% of Delta employees are vaccinated, according to the airline.

The health insurance premium begins Nov. 1.

Unvaccinated employees will also have to wear masks indoors and be required to take a weekly COVID test beginning Sept. 12.

-ABC News' Mina Kaji

Moderna has finalized submission of its application to the Food and Drug Administration for full approval of its COVID-19 vaccine, the company announced Monday.

It's not yet clear how long the FDA will take to review Moderna’s application.

Pfizer completed its vaccine application in May and was granted full approval on Monday.

-ABC News' Eric Strauss

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.

Collectively, the findings could help inform the U.S. government's recommendations about booster shots for the 14 million people who received the single-shot Johnson & Johnson vaccine.

Boosting after six months "appears to be safe, and boosts immune responses substantially," Dr. Dan Barouch, Ph.D., director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, told ABC News.

-ABC News' Sony Salzman

Japan has suspended the use of about 1.63 million doses of Moderna's COVID-19 vaccine due to reported contamination, as the country grapples with surging infections.

Japanese drugmaker Takeda Pharmaceutical Co., which is in charge of distributing the Moderna vaccine in Japan, said in a press release Thursday that it has received reports of foreign substances in some unused vials at multiple inoculation sites. Although some doses might have been administered, Takeda said there have been no reports of safety concerns tied to the affected vials so far.

After consulting with Japan's Ministry of Health, Labor and Wealth, Takeda said it decided as a safety precaution to stop using doses from three separate lots, manufactured in the same production line as the contaminated vials. The company said it has requested Moderna to conduct an emergency investigation into the issue.

For doses from non-suspended lots, Takeda urged people to check the vials for discolouration, foreign substances or other abnormalities before continuing to use. Meanwhile, the Japanese health ministry said it will work with Takeda to supply alternative doses in an effort to minimize the impact on the country's vaccination progress.

Moderna told ABC News that it has put the 1.63 million doses on hold in Japan after being notified that some of the vials may have been contaminated. One of the three lots received "several complaints of particulate matter" in its vials, the American drugmaker said, while the two other adjacent lots were put on hold out of "an abundance of caution" and for continued assurance of quality.

According to Moderna, the manufacturing issue may have come from one of the lines used at its contract manufacturing site in Spain. The Massachusetts-based company said it is looking into the contamination reports and "proactively communicating with Japan’s health authorities and its partners as the investigation proceeds." Moderna added that it remains "committed to working transparently and expeditiously" with its Japanese distribution partner and with regulators to address any potential concerns. No safety or efficacy concerns have been identified so far, the company said.

Moderna noted that the pause in Japan does not impact doses distributed in the United States, or put the American supply at risk in any way.