SANTA CLARA (CBS SF) — On the heels of a Centers for Disease Control and Prevention recommendation, Santa Clara health officials announced Saturday that they were making a third dose of COVID-19 vaccination available for people who have a compromised immune system.

On Friday, the CDC recommended the third dose following the plan’s unanimous endorsement by an expert advisory panel.

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The Food and Drug Administration extend emergency use authorization on Thursday night.

“We have vulnerable immunocompromised populations who are again at risk because of the rapid spread and high transmissibility of the Delta variant,” said Dr. Jennifer Tong, Associate Chief Medical Officer for Santa Clara Valley Medical Center. “For those, a third dose of vaccine offers a substantial additional layer of protection from infection and serious illness.”

Santa Clara officials encouraged eligible residents to contact their primary healthcare provider for consideration of the additional dose. Appointments can also be scheduled through the County’s website, which also includes information about numerous drop-in vaccination sites throughout the county, including local pharmacies.

According to the CDC, those eligible include — individuals being treated for tumors or cancers of the blood; organ transplant patients, including those have received stem cell transplants within the last two years; and those who have diseases that damage the immune system.

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Also on the list were people with advanced or untreated HIV infection, those taking high-dose steroids and those who have chronic medical conditions that can weaken immune response, such as chronic kidney disease.

The CDC estimates that about 2.7% of the population of the United States is immunocompromised.

County health officials said a third dose was available for moderately or severely immunocompromised who have had either Pfizer or Moderna vaccines. The newly expanded FDA order does not extend to individuals who received the Johnson & Johnson vaccine.

The additional dose will be matched to the initial vaccination type, health officials said. The recipient must have completed the initial vaccination series 28 days or more before the third injection.

All County Health System mass vaccination sites will be able to accommodate the newly approved third doses for eligible individuals with community-based mobile sites to begin by mid-week next week.

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For the latest information about COVID-19 vaccinations in Santa Clara County, visit