• William Miller, MD

FDA Approves Pfizer Booster Shot

On September 22nd, the FDA approved the use of a booster shot for the Pfizer COVID vaccine for certain select people who qualify (see below). The CDC made a statement supporting this decision two days later on September 24th. This is different than the “third shot” recommended previously for immunocompromised persons. At this time, this only applies to the Pfizer vaccine, but it is likely that a similar approval will occur for Moderna and possibly Johnson & Johnson.


The Pfizer vaccine was the first to gain approval in December through the Emergency Use Authorization process. Even at that time, it was uncertain whether a booster shot would be needed. In my Miller Report of April 5th, I reported that the immune effect was strongest in the first 3 months and still remained effective out to 8 or 9 months. Newer data confirms that the effectiveness of the Pfizer vaccine is waning somewhat faster than the Moderna. However, even at 9 months it is still effective in reducing the risk of serious illness and death at about 74%, but not as much as in the first 3 months when it is 94% effective.


This does not have so much to do with delta or other variants, but more to do with how our immune system works. Coronaviruses, along with some other upper respiratory viruses, usually cause the common cold. In Northern California, there are 4 different coronaviruses that go around each winter and you can catch the same one over and over. This is because our immunity to coronaviruses is not sustained from year to year. This is also why we are seeing some people get COVID more than once. A similar process takes place with influenza which is one of the reasons we have to get a new flu shot each year. The other reason is that influenza has unique ways of evading our antibody immune system. Fortunately, COVID hasn’t developed that strategy.


The reason behind the FDA and CDC approving a booster shot is to ensure that folks who are at highest risk either because of age, other health problems or high chance of exposure due to work can maintain good levels of circulating antibody when their initial two shots were more than 6 months ago. Here are the specific requirements to qualify for the Pfizer booster:

  • Must be at least 6 months out from getting the second of the two Pfizer vaccine shots AND,

  • Age 65 and older OR,

  • Age 18-64 years old and at high risk for serious COVID based on other health issues OR,

  • Age 18-64 and have frequent exposure to COVID due to occupational (eg. front line healthcare workers) or institutional (eg. inmates in crowded prisons) settings.


The CDC went one step further to state that people in the first two categories should receive the booster, while stating that people in the third category may receive the booster. These are the CDC’s criteria for health problems that qualify a person as high risk: cancer, cerebrovascular disease, chronic kidney disease, COPD, diabetes, heart conditions, obesity, pregnancy or recent pregnancy, smoking (current and former).



As of this writing, the only two places on the Mendocino Coast that are giving the Pfizer booster are Rite Aid and Mendocino Coast Clinics (MCC). In both cases an appointment is required and you will need to bring your vaccination card that shows you have received the two Pfizer doses more than 6 months before. Currently, the pharmacies are required to have a doctor’s note indicating that you qualify. Hopefully, that requirement will be lifted soon so as to make it easier to get the shot.

  • For Rite Aid in Ft Bragg and Willits, visit RiteAid.com/COVID-19 to schedule the appointment.

  • For MCC, call 707-964-1251 to schedule an appointment for their drive through vaccination program which is on Fridays. They expect to give 500 shots each day.


Safeway and CVS currently only have Moderna, but expect to receive Pfizer doses within the next couple of weeks and begin to offer the booster as well. Adventist Health Medical Offices also only has Moderna now, but we expect to receive Pfizer and offer the booster to our patients soon.


In August, the FDA expanded the age cut off down to 12 years old for the Pfizer vaccine. It is expected to further expand the age range by including children from 5 to 11 by the end of October.

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