Facebook Twitter LinkedIn Email

Special Populations

Last reviewed: November 11, 2021

On this page:


As COVID-19 vaccination continues, new data and special considerations have emerged related to a number of patient groups. Here, we provide an overview of current knowledge regarding several key patient populations. CDC also maintains frequently updated patient-facing information about COVID-19 vaccination for specific groups.


In August 2021, FDA authorized and CDC recommended a third dose of COVID-19 mRNA vaccine for certain immunocompromised populations.

Resources related to this announcement include:

This section will be updated with additional information and guidance as it becomes available.


People who have active or prior cancer were largely excluded from COVID-19 vaccine clinical trials, representing <0.01% of mRNA and 0.5% of Janssen vaccinees.

Ongoing evaluation of COVID-19 vaccine immunogenicity in people with cancer focuses predominately on anti-S1/RBD antibody response among people with hematological malignancies. People with chronic lymphocytic leukemia, particularly those receiving active therapy such as B cell depletion, regulators or inhibitors, appear to have poor anti-S antibody sero-response (20-40%) after mRNA vaccination compared to responses among control populations (Herishanu, April 2021; Agha, April 2021). People with multiple myeloma may have somewhat better immune responses in comparison, with evidence of 21% response consistent with neutralizing antibody among a heterogenous population of patients after a single dose of mRNA vaccine, albeit much lower than that seen in healthy controls (Terpos, April 2021). Additionally, anti-S1 IgG antibody response of 56% was seen following the first dose of Pfizer-BioNTech or Oxford-AstraZeneca COVID-19 vaccine (Bird, June 2021). Active therapy was associated with lower vaccine sero-response (74% vs. 48%) in this group. Otherwise, hypogammaglobulinemia and associated “immunoparesis” may be a risk factor for lower vaccine sero-response in both chronic lymphocytic leukemia and MM patients (Herishanu, June 2021; Terpos, April 2021). Ongoing research focuses on B and T cell responses to vaccine antigens, durability of immune responses in the setting of cancer therapies and correlates of real-world protection.


COVID-19 Vaccines in People with Cancer
FAQ maintained by the American Cancer Society.



In October 2021, FDA approved emergency authorization for Pfizer-BioNTech COVID-19 vaccination in children ages 5-11, and CDC's Advisory Committee on Immunization Practices issued subsequent clinical recommendations

CDC and the American Academy of Pediatrics recommend COVID-19 vaccination in all eligible children and adolescents 5 years of age and older.

Although children have experienced lower rates of severe COVID-19 compared with adults, they are still at risk for severe disease (including delayed complications such as multisystem inflammatory syndrome in children, or MIS-C) and can transmit SARS-CoV-2 to others. Initial clinical trials of COVID-19 vaccines excluded children and adolescents, but there are ongoing studies of all currently authorized vaccines in these patient populations. See our main pediatrics page for further details about COVID-19 in children and adolescents.


American Academy of Pediatrics Resource Hub: COVID-19 Vaccine for Children
AAP'a comprehensive collection of guidance and resources for clinicians on pediatric COVID-19 vaccination and communicating about vaccines with families and communities.

COVID-19 Vaccines for Children and Teens
CDC information on COVID-19 vaccinations for children and teens, including eligibility details and information about how to find vaccines.

Interim Recommendations for the Use of Pfizer-BioNTech COVID-19 Vaccine in Children Aged 5–11 Years
Clinical guidance from CDC's Advisory Committee on Immunization Practices.

How to Talk with Parents and Caregivers about COVID-19 Vaccination
CDC guidance for clinicians on counseling parents and guardians about the importance of pediatric COVID-19 vaccination.



Pregnant people are at increased risk of severe COVID-19. However, patients who are pregnant or breastfeeding were excluded from clinical trials of all currently authorized COVID-19 vaccines. CDC and FDA maintain vaccine safety surveillance systems to identify safety signals related to COVID-19 vaccines in this patient population. To date, analysis of post-authorization observational data (Shimabukuro, April 2021) and prospective immunogenicity studies (Gray, March 2021; Collier, May 2021) indicate that mRNA COVID-19 vaccines are safe and immunogenic in pregnant and lactating people. There is also accumulating evidence that mRNA vaccine-induced anti-SARS-CoV-2 antibodies are efficiently transferred across the placenta and are present in breastmilk (Gray, March 2021; Rottenstreich, April 2021; Perl, April 2021; Beharier, May 2021;  Collier, May 2021). 

Current recommendations strongly support vaccination in this population:



American College of Obstetricians and Gynecologists Practice Advisory: Vaccinating Pregnant and Lactating Patients Against COVID-19
ACOG guidance for the use of currently available COVID-19 vaccines in pregnant and lactating patients.

Vaccination Considerations for People Who Are Pregnant or Breastfeeding

CDC information to assist pregnant people with their decision to receive the COVID-19 vaccine.


Solid Organ Transplant

Solid organ transplant recipients were excluded from landmark COVID-19 vaccine clinical trials, representing <0.001% of Janssen COVID-19 vaccinees in published data (N=10). Several single and multicenter cohorts tracking vaccine response in this population predominately focus on anti-spike antibody level as a plausible correlate of neutralizing antibody and thus vaccine immunogenicity (Boyarsky, March 2021; Grupper, April 2021).

Safety and reactogenicity of mRNA vaccination appear reassuring, without a clear signal for unexpected organ rejection or allergy among solid organ transplant recipients (Ou, 2021). In contrast, despite ~100% sero-response among healthy non-solid organ transplant populations after a single mRNA vaccine dose, solid organ transplant anti-spike antibody responses to the full mRNA vaccination series have typically ranged from 30-60% (Boyarsky, March 2021; Grupper, April 2021; Marinaki, April 2021; Benotmane, April 2021). Additionally, among solid organ transplant recipients with detectable anti-spike antibody, levels have typically been lower than those observed in historical or contemporaneous control populations. Older age, more recent transplantation and use of antimetabolite maintenance therapies such as mycophenolate (1.5-2.5 fold lower odds of sero-response) have emerged as associations with low sero-response, particularly among kidney transplant recipients (Boyarsky, March 2021; Grupper, April 2021). Additionally, KT recipients on the selective T cell co-stimulation inhibitor belatacept appear to have very poor humoral responses (<5% anti-spike sero-response) (Chavarot, April 2021). It is not clear if corticosteroid use is associated with poor humoral vaccine responses, nor whether a particular mRNA vaccine platform appears more immunogenic, though early data suggested somewhat improved immunogenicity after the first dose of Moderna mRNA-1273 vaccine (vs. Pfizer-BioNTech 162b2) (Boyarsky, March 2021).

Persistent knowledge gaps include characterization of humoral vaccine responses in non-kidney transplant recipients (e.g., high risk lung recipients), those with recent solid organ transplant (<12 months) and those receiving lymphodepleting induction therapy, as well as clear understanding of real-world seroprotective thresholds. Additionally, immunogenicity of viral vectors such as the Oxford-AstraZeneca and Janssen COVID-19 vaccines is not yet characterized. T cell responses of solid organ transplant recipients after vaccination also remain poorly understood. Given that maintenance immunosuppression promotes exhausted cellular phenotypes to avoid graft rejection, these may further reduce cellular immune response to vaccine antigen. Limited published data include T cell responses measured by interferon-gamma ELISpot in subset of belatacept-treated KT recipients indicating 30% response one month after mRNA vaccination (Chavarot, April 2021). Additional non-peer-reviewed preprint data support that lack of T cell help may be a factor in poor humoral vaccine response in kidney transplant recipients (Rincon-Arevalo, April 2021 - preprint, not peer-reviewed).

Given there are mounting reports of breakthrough infection after vaccination in solid organ transplant recipients, including severe disease among those with evidence of low anti-spike antibody at time of diagnosis (Wadei, April 2021), closing the above knowledge gaps is of critical importance.



Sign up for IDSA's Newsletter
Stay informed with daily resources, media and news.

This website uses cookies

We use cookies to ensure that we give you the best experience on our website. Cookies facilitate the functioning of this site including a member login and personalized experience. Cookies are also used to generate analytics to improve this site as well as enable social media functionality.