Americans can get a booster shot eight months after their second dose.
Natalie Weinstein/CNET

Starting the week of September 20, fully vaccinated will be eligible for a COVID-19 booster shot, eight months after their second dose of the Pfizer and Moderna vaccines, according to a statement Wednesday from public health and medical experts from the U.S. Department of Health and Human Services.

The statement, which also included experts from The Centers for Disease Control and Prevention and the Food and Drug Administration cited evidence that vaccine effectiveness could lessen over time.

“Based on our latest assessment, the current protection against severe disease, hospitalization, and death could diminish in the months ahead, especially among those who are at higher risk or were vaccinated during the earlier phases of the vaccination rollout,” the statement said.

The plan is subject to FDA approval and CDC recommendation on dosage.

The news comes as the more-contagious delta variant continues to spread around the US. Even though breakthrough coronavirus cases caused by the delta variant stack up to less than 1%, a CDC study showed that vaccinated people can both get it and spread it, raising concerns over how to further control the virus.

The FDA and CDC last week signed off on an extra shot of the Pfizer or Moderna COVID-19 vaccines for some immunocompromised people, including solid organ transplant recipients and people receiving treatment for cancers of the blood.

Those who received the Johnson & Johnson vaccine aren’t eligible just yet. The statement said that while they anticipate a booster will be needed, they expect more data in the next few weeks and will create a plan for Johnson & Johnson booster shots, as well.

According to CDC data, about 168.9 million people in the US are fully vaccinated, or 50.9% of the population.

“Our top priority remains staying ahead of the virus and protecting the American people from COVID-19 with safe, effective, and long-lasting vaccines especially in the context of a constantly changing virus and epidemiologic landscape,” the statement said.