Booster Vaccinations in Calvert



The Calvert County Health Department will begin administering COVID vaccine boosters on Monday Sept. 13th. This is a lengthy post because it contains a lot of important evidence and guidance for those considering booster doses. This is an important decision for many in our community and you deserve a thorough overview of current information.

Over the past two weeks, there have been a series of discussions and communications between the physicians at the Calvert Health Department and >60 local clinicians, including representatives from every Calvert primary care practice and many medical specialists, to determine the best course of action regarding booster doses. Since the Delta variant began to cause hospitalizations in early August, 12 breakthrough hospitalizations have occurred in Calvert County. It is important to note that although some hospitalizations have occurred in people who received vaccination, data demonstrate that approximately 100 additional hospitalizations were prevented as a result of vaccine effectiveness. Of the breakthrough cases, ages ranged from early 50s to 80s, and 75% occurred 4-5 months after receiving a 2nd dose. None of these people met the CDC criteria for moderately-severely immunocompromised conditions, although all had at least one chronic health condition that placed them at increased risk for severe COVID illness. Of the five Calvert residents who have died from COVID since early August, one was vaccinated.

After thoroughly reviewing current vaccine research, results from early Israeli booster efforts, and local data on breakthrough cases that have resulted in hospitalizations, consensus recommendations were reached by our local physicians and nurse practitioners. The booster protocol developed by the Health Department is based on these recommendations. It is the goal of the Health Department and local healthcare providers to have a standard based on the best interests of Calvert residents and to provide clear communication and justification for this protocol. Everyone considering booster doses should be aware that protocols have not yet been officially approved by the FDA or CDC.

There is countywide consensus to offer booster doses to everyone 50 and older who received their 2nd vaccination dose at least 4 months ago. (Those who received Johnson & Johnson should see below). Physicians felt that our local empirical evidence, although a small sample size, did not justify a waiting period of 8 months after a second dose. Our chosen timing also places the booster dose at approximately 5 months after the first dose, which is close to the standard 6-month boosters for other vaccines such as hepatitis B, HPV, and polio that have shown long-lasting immunity.

1) The age 50 cutoff does not apply to frontline healthcare workers, nursing home or assisted living facility staff, or first responders. These people have much greater exposure risks than the general public and even if they don't get severely ill, we can't afford to lose this critical workforce for 10 days while they recover. And we certainly don't want sick people trying to work while they are providing healthcare or emergency services. Classroom staff who work with developmentally challenged students who are unable to wear face coverings are also welcomed to receive a booster dose once they reach 4 months from their second vaccination. The age cutoff also doesn't apply to people who live or work in congregate residential settings, including the ARC of Southern MD housing, the domestic violence shelter, county jail, etc. The potential for outbreaks among vulnerable populations is too great.

2) Any licensed clinician is welcome to recommend boosters to any of their patients whom they deem in need. The age 50 cutoff only applies to the general population. If they are caring for a 32 year-old with multiple underlying health problems, licensed clinicians are encouraged to manage her/him as they see fit.

The rationale for this protocol is as follows: Two weeks ago, the White House announced their intention to allow booster doses, starting 9/20/21, for anyone 16 or older, who had received their second mRNA vaccine at least 8 months prior. Those who received J&J remain in booster limbo. The announcement stated that the Sept. 20th date was chosen to give vaccinators time to prepare. No rationale or data were provided to justify the 8-month interval between second and third dose nor the decision to boost anyone 16 or older as opposed to limiting boosters to age groups more likely to develop severe disease and require hospitalization.

The CDC Advisory Committee on Immunization Practices (ACIP) met shortly after the White House announcement. There was a brief presentation on boosters, but there was minimal discussion and no recommendations were made. In the meantime, people are going to pharmacies and other locations where no practice standards are being applied. The CDC estimates that >1 million Americans have already received boosters. Some medical practices have also begun to boost patients. It is our intention to develop an educated, coherent policy for boosters that provides quality guidance to our community instead of having a patchwork access system or having patients act out of fear or based on questionable information gleaned from the internet.

Local clinicians and Health Department staff reviewed available information on the lasting effectiveness of the standard 2-dose vaccine regiment to prevent breakthrough infections and serious illness as well as current evidence on booster doses in those who do not meet the CDC definition of immunocompromised. During the past week, the Maryland Department of Health laboratory reported that 100% of Maryland COVID specimens genotyped were Delta variant, so everything mentioned in this communication will focus on that variant. This week, the ACIP reported that for seniors, full vaccination is 60% effective against infection with Delta, 75% protective against symptomatic infection, and 83% protective against hospitalization. In other words, 1 out of 6 vaccinated seniors is no longer getting protection against severe illness from COVID.

There are three primary reasons that likely account for higher rates of breakthrough infections with Delta. First, the circulating neutralizing antibodies triggered by vaccination wane over time. The rate at which antibodies diminish is likely an age-related phenomenon if evidence from other vaccines can be extrapolated. Second, one of the Delta mutation sites results in stronger covalent bonds between the virus’s spike protein and the ACE receptors on our cells. Another mutation allows more efficient entry through our cell membranes and delivery of viral RNA into our cells. This combination accounts for higher transmission rates, faster onset of illness, and higher virus counts in infected individuals than was seen with earlier strains of COVID. Third, a separate site mutation in Delta has led to conformational changes in the spike protein that decreases attachment of vaccine-derived neutralizing antibodies. Translation: Think of virus proteins like a piece of paper. You can fold the same piece of paper in thousands of different ways resulting in thousands of different shapes. Envision an origami swan or a butterfly. An antibody designed to match the shape of a swan will not align or attach well with the contours of a butterfly. The relative contribution of each of these factors to reduced vaccine efficacy is uncertain at this time.

The same principles apply to decreasing immunity following natural infection. As we’ve all seen by the sky-high infection rates and overflowing hospital wards in states with low vaccination rates, protection from pre-Delta strains of COVID is much less protective than vaccination. The recommendation holds that people who have had previous COVID infections should be vaccinated within 90-days of their illness.

A lecture this past week hosted by the American Public Health Association (APHA) with vaccine experts from UCSF, Duke, and Baylor Schools of Medicine, emphasized that giving two vaccine doses within 1 month is not an ideal way to produce lasting immunity. This regiment made sense to quickly boost immunity when hospitals are overwhelmed last winter and healthcare experts were desperately trying to protect high-risk individuals from dying, but two narrowly spaced doses are not the best long-term strategy. The experts on the national call echoed the thoughts of our local clinicians that many tried and true vaccines for both children and adults boost around 6 months after the initial dose and that's often the last dose needed for many years. We all acknowledge that there is no way to predict whether COVID vaccines will follow the pattern of hepatitis B, HPV, and polio vaccines and provide long-lasting immunity. Long-term immunity will likely hinge more than anything else on the potential evolution of additional COVID mutations.

Our local hospital data since August 1st showed 12 admissions of fully vaccinated people. 10 of the 12 received 2 doses of mRNA vaccines and the others had a single dose of J&J. Given that 93% of vaccinated Calvert residents received Moderna or Pfizer, this ratio is expected. Chart reviews confirmed that none of these people met the CDC criteria for moderate to severe immunocompromising conditions. All, however, had other underlying chronic health conditions.

A recent analysis from Israel took an early look at booster doses given to those 60 and older. This paper is an initial report, so it should not be viewed as conclusive, but Israel has an excellent national health database, and as a result, is able to collect much more comprehensive outcomes than we can ever hope to in the U.S. Their bottom line was as follows, "Twelve days or more after the booster dose we found an 11.4-fold (95% CI: [10.0,12.9]) decrease in the relative risk of confirmed infection, and a >10-fold decrease in the relative risk of severe illness." The authors estimate that a booster dose results in, "protection against severe infection of 95%, similar to the original ‘fresh’ vaccine efficacy reported against the Alpha strain."

Maryland health officials are working on statewide Delta-specific data. It is unlikely they will be able to provide statistical breakdowns (ages, time since last vaccination, immunocompromised status, and chronic conditions) that we have achieved locally. On the APHA call they lamented that there are many areas of the country that are not reporting any COVID data, much less breakthrough hospitalizations. This may in part explain the lack of supporting rationale for an 8-month window between 2nd and 3rd doses and broad-brush recommendation to vaccinate everyone 16 and older.

Available evidence from U.S. and international studies indicate that booster doses have similar safety profiles to earlier doses. mRNA vaccines have been extremely safe. Other than relatively rare allergic reactions, there have been no dangerous side effects in mRNA vaccine recipients 50 and older.

Local healthcare providers also noted that offering COVID boosters in September and October will allow co-administration with flu vaccines. We know that in lots of medical contexts, requiring people to make multiple visits to complete treatment results in missed opportunities to receive important healthcare. Setting an interval of 8 months for boosters will require some high-risk patients to make separate trips to get their COVID and flu vaccinations with the ultimate result of inadequate protection against life-threatening infection. If boosters are available 4 months or more after second doses, patients can get their flu vaccine when they come in for a COVID booster or their COVID booster when they present for a flu vaccine. Either way, this should result in higher vaccination rates against both diseases.


There was significant discussion during a local web conference regarding the age cutoff. No one thought that teens or young adults need boosters at this point. Opinions ranged from age 40 to age 60. Ultimately, unanimous agreement on age 50 was achieved.

We also discussed booster doses following Johnson & Johnson (J&J) vaccination. We all acknowledged that there is insufficient evidence to make strong recommendations. There is evidence indicating safety with either another dose of J&J (as well as safety data from multiple doses of the AstraZeneca adenovirus vaccine) or a supplemental dose of an mRNA vaccine, although this evidence is limited. The FDA is currently evaluating the effectiveness and safety of boosters after J&J. For the moment, decisions on booster doses for those who initially received J&J will need to be made between individuals and their personal healthcare provider. The Health Department will not provide a booster dose to J&J recipients unless they have a note from their doctor or nurse practitioner.

COVID cases have risen dramatically in Calvert since late July. Although case counts in those 65 and older are still lower than in younger age groups thanks to high vaccination rates among seniors, we've gone from 8 diagnosed cases in seniors three weeks ago to 22 cases this past week. Diagnosed cases in those from 0-19 have gone from 35 three weeks ago to 55 this past week. As cases likely continue to increase in school-age children and teens now that they are back in classrooms, cafeterias, and school buses, there is concern that grandchild-to-grandparent transmission may fuel further increases in Calvert residents 50 and older in the coming months.

The best way to get COVID infections under control is to increase the number of Calvert residents who get initial vaccinations. For those who are at higher risk of breakthrough infections, you now have guidelines and rationale to help you decide whether a booster dose is appropriate for you. Again, the information above is based on recommendations from local physicians and nurse practitioners, not the CDC or FDA. You should always consult with your personal healthcare provider if you have additional questions. If you decide to proceed with a booster dose or if you are ready to get your first COVID vaccination, many local medical practices are providing inoculation. You may also schedule a vaccination with the Calvert Health Department. Anyone 12 and older is eligible for initial vaccination.

For booster doses, you must meet the following criteria: 1) Members of the general population must be at least 50 years-old

2) Anyone 16 and older who work in a prioritized job classification, including nursing home staff and others who work in congregate living facilities, frontline healthcare workers, first responders, and teachers and other school staff who work with students unable to wear face coverings due to developmental conditions.

3) Have received either Pfizer or Moderna for their first two doses

4) Must be at least 4 months since their second dose Anyone not meeting these criteria must have a note from their personal healthcare provider indicating the recommendation of a booster dose.


This includes: 1) J&J recipients. Since we have a limited number of J&J doses with no idea when we will receive more, if someone is recommended for a booster, they will receive an mRNA dose if they opt to get it through the Health Department. Their other option is to try to find a local pharmacy with available J&J.

2) People under age 50 unless they have a job that prioritizes them for a booster (see above). We will not give boosters to those who had their second dose (or single dose of J&J) less than 4 months ago.


People who meet CDC criteria for moderate-severe immunocompromising conditions (https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/immuno.html) and are at least 16 years-old may receive an 3rd dose, as long as their previous dose was administered at least 28-days earlier. 3rd doses are considered distinct from booster doses.

Registration for vaccination through the Health Department can be done via web portal https://www.calvertcountycovid19.com/vaccination or calling 410 535-5400 x388. You must bring your CDC vaccination card so we can record your booster dose.

If you can’t locate your CDC card, please bring proof of your previous vaccination dates.

This can be done through the Maryland vaccination database: https://md.myir.net/rorl?next=/ If you are under age 50 and work in a prioritized setting, you must bring proof of your employment (work badge or a note from your employer that verifies you qualify based on your job).


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