The city of Berkeley’s Public Health Division recommended Friday that individuals with compromised immune systems get an additional dose of the Pfizer-BioNTech or Moderna COVID-19 vaccines.

According to a press release from the city, people with moderately or severely compromised immunities should receive their third shot 28 or more days after their second dose of the Pfizer or Moderna vaccine. Such groups include those undergoing treatment for blood cancer, those with organ transplants or people taking medicine to suppress their immune systems, among others.

The press release noted that this guidance aligns with the Center for Disease Control and Prevention guidelines. Additionally, the release adds, there is not yet conclusive data that shows whether or not immunocompromised people who have received the Johnson & Johnson vaccine should receive another dose.

Starting Monday, the city will begin administering third doses to people who are moderately or severely immunocompromised at city-sponsored clinics, according to the release. Those wishing to receive another dose should bring their official vaccine cards so they are given the correct vaccine and can have their third shot documented.

“Vaccines remain the most powerful tool in the fight against COVID-19, including the Delta variant,” the press release concludes. “The City of Berkeley urges all unvaccinated residents 12 and older to get vaccinated as soon as possible.”