Now that the FDA and CDC have authorized the use of third doses of COVID-19 vaccines for certain at-risk individuals, Santa Clara will start giving these extra shots for qualifying people — among those being transplant recipients and cancer patients.

COVID-19 booster shots are an inevitable part of our future. Supplemental COVID-19 vaccine doses — i.e. additional shots of already in-use vaccines, specifically those produced through mRNA technologies — however, are now very much a part of the present moment. And as of this weekend, residents of Santa Clara County can request a third dose of either the Pfizer or Moderna vaccines, should they qualify.

As initially reported by ABC7, the County program went into effect Saturday.

"[Third] doses of the Pfizer and Moderna COVID-19 vaccines have been authorized for patients who are at least 28 days from their last dose and who are moderately or severely immunocompromised," reads text pulled from the Santa Clara County Public Health Department’s COVID-19 vaccine page. "At this time, additional doses after receiving the Johnson and Johnson vaccine have not been authorized. If you are not sure whether you qualify for a 3rd dose of the Moderna or Pfizer vaccines, please consult with your physician."

Additional doses of mRNA COVID-19 vaccines began gaining traction after studies were released that proved their efficacies. These reports show the initial vaccine doses are far less effective for people with weakened immune systems, ranging from 59% to 72%; this is compared to the 90% to 94% effective rate among people without serious immune deficiencies. Receiving a third dose would boost the vaccine’s effectiveness in patients who are immunocompromised  — giving them more protection against the Delta variant, as well.

There's evidence to support that individuals who initially received the Johnson & Johnson vaccine could further benefit from receiving a supplemental dose of an mRNA COVID-19 vaccine. Multiple reports show that the J&J vaccine may not be as effective in preventing infection from the Delta variant as mRNA-based Pfizer and Moderna vaccines — which is why you can now get a supplemental mRNA shot in San Francisco to boost your immunity against the novel pathogen. (Some studies suggest that antibodies in patients receiving mRNA Covid-19 supplement shots show a nearly 50-fold increase in neutralizing virus activity.)

"Those unsure if they fall under the eligible category should consult with a medical professional," said the county. However, it's safe to say that any person with an underlying immunodeficiency illness, those being treated for or are recovering from cancer, or patients who’ve received an organ transplant would likely qualify for an additional mRNA vaccine dose.

Santa Clara's health department notes that the additional dose should match the original vaccine series that the patient received (i.e., if you have completed the Pfizer vaccine series, you should receive an additional dose of Pfizer). Eligible people will need to bring a copy of their COVID-19 vaccine record.

Appointments can be scheduled at

Related: Dr. Grant Colfax Does Not Want You Calling New Supplemental mRNA Vaccine Program a 'Booster'

If You Got the Johnson & Johnson Shot, SF General Will Give You a 'Supplemental' Pfizer or Moderna Shot

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