Question:
Dr. Chicoine, At least 1 country (Israel) is providing Pfizer booster shots to adults with compromised immunity. What do you think of this for adults with Down syndrome – do they generally fit into the “compromised immunity” category? My son also has tetralogy of Fallot (repaired) and a prosthetic pulmonary valve, as well as sleep apnea and asthma. Also, would a Pfizer booster be appropriate for someone who received the Moderna vaccine.
Answer:
Those are good questions for which we do not have definite answers yet. In the United States, we are waiting for guidance from the Centers for Disease Control and Prevention (CDC).
Here is what we do know:
People with Down syndrome (DS) and other intellectual disabilities are at greater risk from COVID-19 infections.
- A study by Gleason et al. (2021) showed that “having an intellectual disability was the strongest independent risk factor for presenting with a Covid-19 diagnosis and the strongest independent risk factor other than age for Covid-19 mortality.”
- A study by Huls et al. (2021) showed that adults with DS are at particularly high risk for COVID-19 mortality, especially those over the age of 40 and those with risk factors. People with DS over the age of 40 had a 2.9 times greater risk of mortality from COVID-19 compared to people without DS.
- The CDC includes Down syndrome on the list of adults of any age who are more likely to become severely ill from COVID-19.
How long does immunity last after either becoming infected with COVID-19 or getting the COVID-19 vaccine?
- A review of what we know about how long COVID-19 immunity lasts was published on June 30, 2021. The author concluded that the length of time one appears to be immune is 6-12 months or more but noted that more research is needed.
- Information specific to DS is pending (studies are ongoing).
If immunity does not last, should we get a booster shot?
- Pfizer and BioNTech have said that a third dose of their COVID-19 vaccine may be necessary 6-12 months after full vaccination. They plan to submit more data to the FDA and other regulatory authorities in the coming weeks.
- According to Reuters, several countries are considering booster immunizations. Some factors they are weighing include when to administer a booster and who should be prioritized for a booster (e.g., the elderly and immunocompromised).
- Currently in the United States, the CDC is not recommending a booster for individuals who have been fully vaccinated (either with a 2-dose mRNA COVID-19 vaccine series or single dose of Janssen COVID-19 vaccine). According to the CDC website, “The need for and timing of COVID-19 booster doses have not been established. No additional doses are recommended at this time.”
- Currently, the CDC is not recommending mixing the vaccines. In other words, if you received Pfizer for the first dose, get Pfizer for the second dose. If a booster dose is ultimately recommended, particularly if there is not approval for all the vaccines to be given as a booster, the CDC would have to address that issue at that time.
What about people with immune deficiencies?
- Many people with DS are considered to have impaired function of their immune systems (immune deficiency).
- As you stated, Israel is offering a third dose to some individuals due to concerns that COVID-19 immunity may decrease over time. The Washington Post reported, “Israel’s Ministry of Health on Monday began offering a third dose of the Pfizer coronavirus vaccine to severely immunocompromised adults in what health experts say could be the first phase of an experiment to provide coronavirus booster shots for older people and the most vulnerable.” Reuters reported the same information.
- In Gleason et al. (2021), the authors advocated that people with intellectual disabilities and their caregivers should be prioritized for COVID-19 vaccination and health care services due to their higher risk. One of the factors that contributes to the higher risk appears to be immune deficiency. We do not have data at this time as to whether that suggests people with intellectual disabilities should also get priority for a booster.
- However, booster doses may not be appropriate for all people with immune deficiency. The American College of Cardiology summarized a few small studies that looked at giving three-dose regiments to transplant recipients who are on medications that suppress the immune system. The studies suggested that giving three doses of COVID-19 vaccines to immunocompromised people who did not have a strong immune response after two doses may provide additional protection. However, the American College of Cardiology noted that the three-dose regimen poses risks to some immunocompromised individuals. These risks include organ rejection and autoimmune disease exacerbation. They stated that further study is needed. The authors concluded, “In the absence of robust herd immunity or more effective vaccination techniques, continued physical distancing, mask use, social restrictions, and vaccination of close contacts will remain essential for the health and safety of immunocompromised individuals.”
Are there other reasons why booster doses may not be recommended at this time?
As the percentage of people who are vaccinated increases, it becomes more and more difficult for a virus to spread and mutate. It may be more effective to focus on getting as many people immunized with the present one or two-shot regimens before offering boosters. An article by Altmann et al. (2021) concluded, “Ultimately, the best defense against emergence of further variants of concern is a rapid, global, vaccination campaign – in concert with other public health measures to block transmission. A virus that cannot transmit and infect others has no chance to mutate.”
Conclusion
While we wait for the results of studies on the length of time immunity lasts and the potential benefit of a booster for people with and without immunodeficiency, experts continue to recommend that people get immunized as soon as possible to:
- Protect themselves
- Limit potential exposure for those who have immunodeficiency that may make the vaccine less effective
- Reduce the emergence of COVID-19 variants
- Reduce the impact of the COVID-19 pandemic
This information is current as of July 20, 2021. For the most up-to-date information, please see the CDC website.