Booster? Third Dose? What’s the Difference?

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You’ve probably heard…Pfizer booster doses are now authorized for certain individuals. But what does this mean? And what is the difference between a Booster and a third dose? After all, haven’t third doses been available for a while now?

If you are confused, you’re not alone! Have questions? We’ve got your answers!

What’s the difference between a third dose and a booster?

These terms shouldn’t be used interchangeably! They do—in fact—mean two separate things.

A third dose (also known as an additional dose) is for people who are immunocompromised. Sometimes people who are immunocompromised do not build enough protection when they first get fully vaccinated. When this happens, getting another dose of a vaccine can help them build more protection against the disease. Third doses of Moderna or Pfizer vaccine are currently available for certain immunocompromised individuals.

A booster refers to a dose of a vaccine that is given to someone who built enough protection after vaccination, but that protection decreased over time (waning immunity). This is why you need a tetanus booster every 10 years, because the protection from your childhood tetanus vaccine wanes over time. Only Pfizer boosters are currently available for certain populations.

Am I eligible for a third dose?

Currently, the CDC is recommending that moderately to severely immunocompromised people receive a third dose. This includes people who have:

  • Been receiving active cancer treatment for tumors or cancers of the blood
  • Received an organ transplant and are taking medicine to suppress the immune system
  • Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
  • Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced or untreated HIV infection
  • Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response

People should talk to their healthcare provider about their medical condition, and whether getting a third dose is appropriate for them.

A person receiving a third dose should get it at least 28 days after dose two. When possible, the individual should receive the same vaccine (Moderna or Pfizer) as the first two doses but may receive the other mRNA vaccine brand if the original vaccine is not available.

At this time, no third dose is recommended for people who had the Johnson & Johnson (J&J) vaccine. People who received J&J should not get a second dose of either J&J or a dose of an mRNA vaccine. Additionally, people with competent immune systems should not receive a third dose.

Am I eligible for a booster?

At this time, only Pfizer Boosters are authorized, and are only for specific groups. First off, only those who received a first and second dose of Pfizer COVID-19 vaccine should seek out a booster dose at this time. Those who initially received Moderna or J&J will need to wait (see more about this below).

It is recommended that the following people receive a Pfizer booster dose:

  • People 65 and older
  • People 18 and older living in long-term care settings
  • People 50 – 64 with underlying medical conditions or those at increased risk of social inequities

Additionally, the following people may receive a booster dose of the Pfizer vaccine:

Eligible people will need to wait to receive their Pfizer booster until at least 6 months after their second dose of Pfizer. This means that—at the time of this article—only those who received their second dose in March or earlier should seek out a booster.

Additional populations may be recommended to receive a Pfizer booster shot as more data become available.

Is a third dose or booster really necessary?

A third dose may prevent serious and possibly life-threatening COVID-19 disease in people with compromised immune systems who may not have responded to their initial vaccine series.

Although we still have much to learn, early findings are very encouraging. Research published by the Israeli Health Ministry suggests that a third dose of the Pfizer-BioNTech COVID-19 vaccine significantly improves protection for those 60 and older from infection and serious illness, compared to those who received just two doses.

As for boosters, the COVID-19 vaccines continue to be very effective at reducing the risk of severe disease. Data show that protection against COVID-19 from vaccination begins to decrease over time as it does with other diseases like tetanus or whooping cough.

Paired with the dominance of the delta variant, we are starting to see evidence of reduced protection against mild and moderate disease. As a result, the CDC now recommends booster shots for certain individuals to increase—and extend—protection against the virus.

What if I got Moderna or the J&J single dose vaccine?

At this time, there are not yet booster recommendations for people who received the Moderna or J&J COVID-19 vaccines. The CDC and FDA will evaluate data in the coming weeks and may make additional recommendations for other vaccine types.

How can I make an appointment?

If you’re looking for a third dose of Moderna or Pfizer vaccine, talk with your health care provider first to make sure that a third dose is right for you. If so, there are many vaccine provider locations available to you, including the Skagit County Fairgrounds.  

Looking for a Pfizer booster? Use the Vaccine Locator online tool, check in with your local pharmacy, or give the COVID Hotline a call at 1–800–525–0127, then press #.

Folks can also schedule an appointment for a Pfizer booster at the Skagit County Fairgrounds. To make an appointment, use the PrepMod online appointment finder and search for “Skagit County Public Health” under Name of Location.

Please note that appointments are limited at this time. If no appointments appear when you search, check back the following Monday for newly added appointments. The COVID Hotline is also available if you need further assistance: 1–800–525–0127, then press #.

What should I bring with me?

When seeking out a third dose or booster, please remember to bring your Vaccination Card with you! Can’t find it? Visit MyIR Mobile to pull your vaccination record or call the State COVID-19 Hotline for assistance at 1–800–525–0127, then press #.


Public Health Expanding Hours of Operation at the Fairgrounds Testing and Vaccination Site Beginning October 4th

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September 28, 2021

The Skagit County Fairgrounds Testing and Vaccination Site will be expanding its hours of operatioThe Skagit County Fairgrounds Testing and Vaccination Site will be expanding its hours of operation next week to better serve the community and reduce wait times. Beginning on Monday October 4, the new operating hours will be from 3 p.m. – 7 p.m., Monday, Tuesday, Thursday, and Friday. The site will no longer operate on Wednesdays.

“This change was necessary given current demand for testing here in Skagit County. We’ve heard from the community that more evening testing options are needed so we are pleased to be able to respond to these needs.”

Jennifer Johnson, Skagit County Public Health Director

Vaccination services continue to be offered to all people 12 years and older. People can access a first or second dose of Pfizer or Moderna, or a single-dose of Johnson & Johnson, when supplies are available. Third doses of Pfizer and Moderna are also available to certain immunocompromised individuals. Please speak with your healthcare provider about whether an additional dose is appropriate for you.

Beginning September 29th, Pfizer booster doses will be available BY APPOINTMENT ONLY for eligible individuals who received Pfizer for their first and second dose. If you received your second dose of Pfizer in March 2021 or earlier, you may now be eligible for a booster dose if you meet the criteria below. Those eligible for a Pfizer booster dose include:

  • People 65 years and older and residents in long-term care settings.
  • People aged 18–64 years with underlying medical conditions.
  • People aged 18-64 years who are at increased risk for COVID-19 exposure and transmission because of occupational or institutional setting.

To make an appointment for a Pfizer booster, please use the PrepMod online appointment finder. Under “Search By Name of Location,” enter “Skagit County Public Health.” If there are no appointment dates listed, please check back in a few days. For assistance, call (360) 416-1500.

Snapshot from PrepMod

Please bring your Vaccination Card with you when coming for a second or third dose, or a Pfizer booster dose.
For more info about the CDC guidance: https://bit.ly/3i73NKL.

As a reminder, antigen testing is now limited to individuals who live, work, or go to school in Skagit County. Those coming for testing must be 5 years or older and must (a) be currently symptomatic or (b) have had recent exposure to COVID-19.

Those seeking testing or vaccination, and who meet the above criteria, are asked to come to the South Gate Entrance at 501 Taylor Street in Mount Vernon. Services are free; no appointment is required for testing, or vaccination 1st, 2nd, and 3rd doses. Appointments will be required for Pfizer booster doses beginning September 29th. 

Remember: The Skagit County Fairgrounds is not the only testing or vaccine location here in Skagit County, and folks should anticipate long wait times when coming to the site. Site capacity is limited, and vehicles will be turned away if/when the site reaches its daily capacity limits. A full list of testing and vaccine providers in Skagit County can be found on our website: www.skagitcounty.net/coronavirus.

Lastly, please do not arrive more than 30 minutes before the site opens to keep traffic off Cleveland Avenue. For more information about the Skagit County Fairgrounds Testing and Vaccination Site, please go to our website at www.skagitcounty.net/coronavirus or call (360) 416-1500.