Effectiveness and safety of SARS-CoV-2 vaccine in Inflammatory Bowel Disease patients: a systematic review, meta-analysis and meta-regression

A booster dose of SARS-COV-2 vaccine improves suboptimal seroconversion rates in patients with inflammatory bowel disease. Results of a prospective multicenter study of GETECCU (VACOVEII study)

BACKGROUND

The response to SARS-CoV-2 vaccination decreases in inflammatory bowel disease (IBD) patients, specially under anti-TNF treatment. However, data on medium-term effectiveness are limited, specially using new recommended seroconversion rate (>260BAU/mL). Our aim was to evaluate the 6-month>260 BAU-seroconversion rate after full vaccination and after booster-dose.

METHODS

VACOVEII is a Spanish multicenter, prospective study promoted by GETECCU. IBD patients full vaccinated against SARS-CoV-2 and without previous COVID-19 infection, treated or not with immunosuppressants, were included. The booster dose was administered 6 months after the full vaccination. Seroconversion was set at 260BAU/mL, according to most recent recommendations and was assessed 6 months after the full vaccination and 6 months after booster-dose.

RESULTS

Between October 2021 and March 2022, 313 patients were included (124 no treatment or mesalazine; 55 immunomodulators; 87 anti-TNF; 19 anti-integrin; and 28 ustekinumab). Most patients received mRNA-vaccines (86%). Six months after full vaccination, overall seroconversion rate was 44.1%, being significantly lower among patients on anti-TNF (19.5%, p<0.001) and ustekinumab (35.7%, p=0.031). The seroconversion rate after booster was 92%. Again, anti-TNF patients had a significantly lower seroconversion rate (67%, p<0.001). mRNA-vaccine improved seroconversion rate (OR 11.720 [95% CI 2.26-60.512]).

CONCLUSION

The full vaccination regimen achieves suboptimal response in IBD patients, specially among those anti-TNF or ustekinumab. The booster dose improves seroconversion rate in all patients, although it remains limited in those treated with anti-TNF. These results reinforce the need to prioritize future booster doses in patients on immunosuppressants therapy, specially under anti-TNF, and using mRNA-vaccines.

Feasibility and Effectiveness of Vaccines for COVID-19: An Umbrella Review

Introduction

In January 2020, WHO declared the 2019 Coronavirus Disease (COVID-19) a pandemic. Though COVID-19 vaccines are recommended, ongoing surveillance is crucial due to potential unforeseen events. Evaluation of long-term effectiveness and safety and addressing emerging variants are vital. This study integrates systematic reviews to assess COVID-19 vaccine efficacy, immunogenicity, and safety comprehensively.

Methods

This study was an umbrella review study on the feasibility and effectiveness of vaccines for COVID-19. We conducted a comprehensive search in PubMed, Web of Sciences, and Scopus, using MeSH terms and keywords related to COVID-19 vaccines. Inclusion criteria comprised peer-reviewed systematic reviews and meta-analyses in English, focusing on feasibility and effectiveness. Exclusion criteria targeted non-systematic reviews exclusively on vaccine safety and duplicates. Two independent reviewers screened and resolved discrepancies. Data extraction included key details. Methodological quality was assessed using the ROBIS tool. Data synthesis involves narrative and, if applicable, quantitative synthesis (meta-analysis). Reporting followed PRISMA guidelines.

Results

A total of 32 systematic reviews were included in the study, of which 20 also conducted a meta-analysis. The studies investigated in the included reviews ranged from 7 to 74. The included articles were conducted in various countries around the globe. The findings indicated that COVID-19 vaccines are generally safe and effective for individuals with various medical conditions. The overall risk of bias for the included studies was assessed as low risk.

Conclusion

The study outcomes indicated that mRNA vaccines exhibit a higher incidence of adverse events but demonstrate greater efficacy. Conversely, inactivated and protein subunit vaccines are safer but exhibit lower efficiency. Moreover, the vaccine is considered safe for individuals with specific conditions such as inflammatory bowel disease, solid organ transplant recipients, children, pregnant individuals, and those with hematologic problems. Ultimately, the acceptance of the COVID-19 vaccine among individuals is influenced by various factors, including geographic, socioeconomic, and pandemic-related considerations.

Clinical characteristics and the risk factors for the exacerbation of symptoms in patients with inflammatory bowel disease during the COVID-19 pandemic

Background

In 2023, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant caused a large-scale outbreak of coronavirus disease 2019 (COVID-19) in China. It is not clear the risk factors that lead to the exacerbation of symptoms in patients with inflammatory bowel disease (IBD) after COVID-19 infection. Our study aims to find out the risk factors for the exacerbation of IBD-related symptoms in IBD patients with COVID-19 infection and to provide guidance for the clinical management of IBD.

Methods

This is a retrospective, observational study. The online questionnaire was distributed to conduct a survey to collect demographic, clinical, and IBD related characteristics in IBD patients. Univariate and multivariate regression analyses were conducted to assess the independent effects.

Results

In total, 534 cases of IBD patients were analyzed in our study. Among them, 466 (87.3%) cases diagnosed with COVID-19, 160 (34.3%) cases experienced exacerbation of IBD symptoms, and 84 (18.0%) patients opted for medication discontinuation. Male sex (OR 2.04, 95% CI 1.34-3.49, p = 0.001), and the decrease in body mass index (BMI) (OR 0.93, 95% CI 0.87-1.00, p = 0.035) were positively correlated with the exacerbation of IBD symptoms. Furthermore, the medication discontinuation (OR 2.60, 95% CI 1.58-4.30, p < 0.001) was strongly positively correlated with the exacerbation of IBD symptoms. No significant association was seen between age, comorbidities, smoking, disease activity, vaccination, therapy for COVID-19 and the worsening of IBD symptoms.

Conclusion

This study confirms that the infection rate of COVID-19 in China IBD patients was comparable to the general population. Male sex, the decrease in BMI and medication discontinuation are significant risk factors for the exacerbation of IBD-related symptoms in IBD patients with COVID-19 infection.

Immunogenicity, Effectiveness, and Safety of COVID-19 Vaccines among Patients with Immune-Mediated Dermatological Diseases: A Systematic Review and Meta-analysis

Immunocompromised individuals, primarily attributable to using immunosuppressants, face heightened COVID-19 risks. Despite the proven efficacy of COVID-19 vaccines, their impact on patients with immune-mediated dermatological diseases remains unclear. This study aims to thoroughly examine vaccine immunogenicity, effectiveness, and safety in immune-mediated dermatological disease patients. Clinical studies in adults that compared vaccinated immune-mediated dermatological disease patients with vaccinated healthy controls or unvaccinated immune-mediated dermatological disease patients in terms of vaccine immunogenicity, COVID-19 infection, adverse events, or exacerbation of immune-mediated dermatological diseases were searched via electronic databases. Seventeen studies (1,348,690 participants) were included. Seroconversion rates between immune-mediated dermatological disease patients and healthy controls were not different. However, among individuals aged ≤55 years, immune-mediated dermatological disease patients had lower mean anti-SARS-CoV-2 IgG levels. Immunosuppressed immune-mediated dermatological disease patients also had lower titres and were less likely to achieve T-cell response. In terms of safety, the risk of adverse events was higher in atopic dermatitis patients, but those with psoriasis had a reduced risk. Additionally, immunosuppressed patients had fewer adverse events. Vaccinated immune-mediated dermatological disease patients had a lower risk of COVID-19 infection than unvaccinated patients but a higher risk than healthy controls; however, disease exacerbation may be induced. In conclusion, immune-mediated dermatological diseases showed a reduced vaccine response in our meta-analysis, yet vaccination remained effective against COVID-19 infection and well tolerated.

Postvaccination Symptoms After SARS-CoV-2 mRNA Vaccination Among Patients With Inflammatory Bowel Disease: A Prospective, Comparative Study

BACKGROUND

Vaccine hesitancy is prevalent among people with IBD, in part due to insufficient evidence regarding comparative safety of vaccines in this population.

METHODS

We conducted a nationwide comparative study of postvaccination symptoms among those with IBD and health care workers (HCWs) without IBD. Symptom frequency, severity, and duration were measured. Continuous and categorical data were analyzed using Wilcoxon rank-sum and Fisher's exact test. Regression analysis was used to adjust for confounding variables.

RESULTS

We had 2910 and 2746 subjects who completed a survey after dose 1 (D1) and dose 2 (D2) respectively (D1: HCW = 933, IBD = 1977; D2: HCW = 884, IBD = 1862). Mean age was 43 years, 67% were female, and 23% were nonwhite; 73% received BNT162b2 (Pfizer) including almost all HCWs and 60% of IBD patients. Most postvaccine symptoms were mild and lasted ≤2 days after both doses in both groups. Health care workers experienced more postvaccination symptoms overall than IBD patients after each dose (D1: 57% vs 35%, P < .001; D2: 73% vs 50%, P < .001). Gastrointestinal symptoms were noted in IBD more frequently after D1 (5.5% vs 3%, P = .003) but not after D2 (10% vs 13%, P = .07). Inflammatory bowel disease subjects who received mRNA-1273 (Moderna) reported more overall symptoms compared with BNT162b2 (57% vs 46%, P < .001) including gastrointestinal symptoms (12% vs 8%, P = .002) after D2.

CONCLUSIONS

People with IBD had fewer postvaccination symptoms following the first 2 doses of SARS-CoV-2 mRNA vaccines than HCWs. Among those with symptoms, most symptoms were mild and of short duration.

mRNA-1273 vaccinated inflammatory bowel disease patients receiving TNF inhibitors develop broad and robust SARS-CoV-2-specific CD8+ T cell responses

SARS-CoV-2-specific CD8+ T cells recognize conserved viral peptides and in the absence of cross-reactive antibodies form an important line of protection against emerging viral variants as they ameliorate disease severity. SARS-CoV-2 mRNA vaccines induce robust spike-specific antibody and T cell responses in healthy individuals, but their effectiveness in patients with chronic immune-mediated inflammatory disorders (IMIDs) is less well defined. These patients are often treated with systemic immunosuppressants, which may negatively affect vaccine-induced immunity. Indeed, TNF inhibitor (TNFi)-treated inflammatory bowel disease (IBD) patients display reduced ability to maintain SARS-CoV-2 antibody responses post-vaccination, yet the effects on CD8+ T cells remain unclear. Here, we analyzed the impact of IBD and TNFi treatment on mRNA-1273 vaccine-induced CD8+ T cell responses compared to healthy controls in SARS-CoV-2 experienced and inexperienced patients. CD8+ T cells were analyzed for their ability to recognize 32 SARS-CoV-2-specific epitopes, restricted by 10 common HLA class I allotypes using heterotetramer combinatorial coding. This strategy allowed in-depth ex vivo profiling of the vaccine-induced CD8+ T cell responses using phenotypic and activation markers. mRNA vaccination of TNFi-treated and untreated IBD patients induced robust spike-specific CD8+ T cell responses with a predominant central memory and activated phenotype, comparable to those in healthy controls. Prominent non-spike-specific CD8+ T cell responses were observed in SARS-CoV-2 experienced donors prior to vaccination. Non-spike-specific CD8+ T cells persisted and spike-specific CD8+ T cells notably expanded after vaccination in these patient cohorts. Our data demonstrate that regardless of TNFi treatment or prior SARS-CoV-2 infection, IBD patients benefit from vaccination by inducing a robust spike-specific CD8+ T cell response.

Geography Influences Susceptibility to SARS-CoV-2 Serological Response in Patients With Inflammatory Bowel Disease: Multinational Analysis From the ICARUS-IBD Consortium

BACKGROUND

Beyond systematic reviews and meta-analyses, there have been no direct studies of serological response to COVID-19 in patients with inflammatory bowel disease (IBD) across continents. In particular, there has been limited data from Asia, with no data reported from India. The ICARUS-IBD (International study of COVID-19 Antibody Response Under Sustained immunosuppression in IBD) consortium assessed serological response to SARS-CoV-2 in patients with IBD in North America, Europe, and Asia.

METHODS

The ICARUS-IBD study is a multicenter observational cohort study spanning sites in 7 countries. We report seroprevalence data from 2303 patients with IBD before COVID-19 vaccination between May 2020 and November 2021. SARS-CoV-2 anti-spike and anti-nucleocapsid antibodies were analyzed.

RESULTS

The highest and lowest SARS-CoV-2 anti-spike seropositivity rates were found in Asia (81.2% in Chandigarh and 57.9% in Delhi, India; and 0% in Hong Kong). By multivariable analysis, country (India: odds ratio [OR], 18.01; 95% confidence interval [CI], 12.03-26.95; P < .0001; United Kingdom: OR, 2.43; 95% CI, 1.58-3.72; P < .0001; United States: OR, 2.21; 95% CI, 1.27-3.85; P = .005), male sex (OR, 1.46; 95% CI, 1.07-1.99; P = .016), and diabetes (OR, 2.37; 95% CI, 1.04-5.46; P = .039) conferred higher seropositivity rates. Biological therapies associated with lower seroprevalence (OR, 0.22; 95% CI, 0.15-0.33; P < .0001). Multiple linear regression showed associations between anti-spike and anti-nucleocapsid titers with medications (P < .0001) but not with country (P = .3841).

CONCLUSIONS

While the effects of medications on anti-SARS-CoV-2 antibody titers in patients with IBD were consistent across sites, geographical location conferred the highest risk of susceptibility to serologically detectable SARS-CoV-2 infection. Over half of IBD patients in India were seropositive prior to vaccination. These insights can help to inform shielding advice, therapeutic choices, and vaccine strategies in IBD patients for COVID-19 and future viral challenges.

STAR SIGN study: Evaluation of COVID-19 vaccine efficacy against the SARS-CoV-2 variants BQ.1.1 and XBB.1.5 in patients with inflammatory bowel disease

BACKGROUND

Vaccine-elicited immune responses are impaired in patients with inflammatory bowel disease (IBD) treated with anti-TNF biologics.

AIMS

To assess vaccination efficacy against the novel omicron sublineages BQ.1.1 and XBB.1.5 in immunosuppressed patients with IBD.

METHODS

This prospective multicentre case-control study included 98 biologic-treated patients with IBD and 48 healthy controls. Anti-spike IgG concentrations and surrogate neutralisation against SARS-CoV-2 wild-type, BA.1, BA.5, BQ.1.1, and XBB.1.5 were measured at two different time points (2-16 weeks and 22-40 weeks) following third dose vaccination. Surrogate neutralisation was based on antibody-mediated blockage of ACE2-spike protein-protein interaction. Primary outcome was surrogate neutralisation against tested SARS-CoV-2 sublineages. Secondary outcomes were proportions of participants with insufficient surrogate neutralisation, impact of breakthrough infection, and correlation of surrogate neutralisation with anti-spike IgG concentration.

RESULTS

Surrogate neutralisation against all tested sublineages was reduced in patients with IBD who were treated with anti-TNF biologics compared to patients treated with non-anti-TNF biologics and healthy controls (each p ≤ 0.001) at visit 1. Anti-TNF therapy (odds ratio 0.29 [95% CI 0.19-0.46]) and time since vaccination (0.85 [0.72-1.00]) were associated with low, and mRNA-1273 vaccination (1.86 [1.12-3.08]) with high wild-type surrogate neutralisation in a β-regression model. Accordingly, higher proportions of patients treated with anti-TNF biologics had insufficient surrogate neutralisation against omicron sublineages at visit 1 compared to patients treated with non-anti-TNF biologics and healthy controls (each p ≤ 0.015). Surrogate neutralisation against all tested sublineages decreased over time but was increased by breakthrough infection. Anti-spike IgG concentrations correlated with surrogate neutralisation.

CONCLUSIONS

Patients with IBD who are treated with anti-TNF biologics show impaired neutralisation against novel omicron sublineages BQ.1.1 and XBB.1.5 and may benefit from prioritisation for future variant-adapted vaccines.

Is Vaccination Against COVID-19 Associated With Inflammatory Bowel Disease Flare? Self-Controlled Case Series Analysis Using the UK CPRD

INTRODUCTION

To investigate the association between vaccination against coronavirus disease 2019 (COVID-19) and inflammatory bowel disease (IBD) flare.

METHODS

Patients with IBD vaccinated against COVID-19 who consulted for disease flare between December 1, 2020, and December 31, 2021, were ascertained from the Clinical Practice Research Datalink. IBD flares were identified using consultation and corticosteroid prescription records. Vaccinations were identified using product codes and vaccination dates. The study period was partitioned into vaccine-exposed (vaccination date and 21 days immediately after), prevaccination (7 days immediately before vaccination), and the remaining vaccine-unexposed periods. Participants contributed data with multiple vaccinations and IBD flares. Season-adjusted incidence rate ratios (aIRR) and 95% confidence intervals (CI) were calculated using self-controlled case series analysis.

RESULTS

Data for 1911 cases with IBD were included; 52% of them were female, and their mean age was 49 years. Approximately 63% of participants had ulcerative colitis (UC). COVID-19 vaccination was not associated with increased IBD flares in the vaccine-exposed period when all vaccinations were considered (aIRR [95% CI] 0.89 [0.77-1.02], 0.79 [0.66-0.95], and 1.00 [0.79-1.27] in IBD overall, UC, and Crohn's disease, respectively). Analyses stratified to include only first, second, or third COVID-19 vaccinations found no significant association between vaccination and IBD flares in the vaccine-exposed period (aIRR [95% CI] 0.87 [0.71-1.06], 0.93 [0.75-1.15], and 0.86 [0.63-1.17], respectively). Similarly, stratification by COVID-19 before vaccination and by vaccination with vectored DNA or messenger RNA vaccine did not reveal an increased risk of flare in any of these subgroups.

DISCUSSION

Vaccination against COVID-19 was not associated with IBD flares regardless of prior COVID-19 infection and whether messenger RNA or DNA vaccines were used.

Impact of COVID-19 in individuals with and without pre-existent digestive disorders with a particular focus on elderly patients

Coronavirus disease 2019 (COVID-19) has several extrapulmonary symptoms. Gastrointestinal (GI) symptoms are among the most frequent clinical manifestations of COVID-19, with severe consequences reported in elderly patients. Furthermore, the impact of COVID-19 on patients with pre-existing digestive diseases still needs to be fully elucidated, particularly in the older population. This review aimed to investigate the impact of COVID-19 on the GI tract, liver, and pancreas in individuals with and without previous digestive diseases, with a particular focus on the elderly, highlighting the distinctive characteristics observed in this population. Finally, the effectiveness and adverse events of the anti-COVID-19 vaccination in patients with digestive disorders and the peculiarities found in the elderly are discussed.

Nationwide experiences with trough levels, durability, and disease activity among inflammatory bowel disease patients following COVID-19 vaccination

Background

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has complicated the management of inflammatory bowel diseases (IBD).

Objectives

This study aimed to assess the efficacy of different anti-SARS-CoV-2 vaccines under different treatments in IBD patients and identify predictive factors associated with lower serological response, including anti-tumor necrosis factor (anti-TNF) drug levels.

Design

A prospective, double-center study of IBD patients was conducted following messenger ribonucleotide acid (mRNA) and non-mRNA anti-SARS-CoV-2 vaccination.

Methods

Healthy control (HC) patients were enrolled to reduce bias. Baseline and control samples were obtained 14 days after the second dose to assess the impact of conventional and biological treatments. Clinical and biochemical activity, serological response level, and anti-TNF drug levels were measured.

Results

This study included 199 IBD (mean age, 40.9 ± 12.72 years) and 77 HC participants (mean age, 50.3 ± 12.36 years). Most patients (76.9%) and all HCs received mRNA vaccines. Half of the IBD patients were on biological treatment (anti-TNF 68.7%). Biological and thiopurine combined immunomodulation and biological treatment were associated with lower serological response (p < 0.001), and mRNA vaccination promoted better antibody levels (p < 0.001). Higher adalimumab levels caused lower serological response (p = 0.006). W8 persistence of anti-SARS-CoV-2 level was equal in IBD and HC groups. Vaccination did not aggravate clinical disease activity (p = 0.65).

Conclusion

Anti-SARS-CoV-2 vaccination is considerably efficacious in IBD patients, with mRNA vaccines promoting better antibody levels. The negative impact of combined biological treatment, especially with high adalimumab drug levels, on serological response to vaccination should be considered. Although midterm durability of vaccination is encouraging, more data are needed to expand the existing understanding on this issue.

Reduced humoral response to two doses of COVID-19 vaccine in patients with inflammatory bowel disease: Data from ESCAPE-IBD, an IG-IBD study

BACKGROUND

Patients on immunosuppressive drugs have been excluded from COVID-19 vaccines trials, creating concerns regarding their efficacy.

AIMS

To explore the humoral response to COVID-19 vaccines in patients with inflammatory bowel disease (IBD) METHODS: Effectiveness and Safety of COVID-19 Vaccine in Patients with Inflammatory Bowel Disease (IBD) Treated with Immunomodulatory or Biological Drugs (ESCAPE-IBD) is a prospective, multicentre study promoted by the Italian Group for the study of Inflammatory Bowel Disease. We present data on serological response eight weeks after the second dose of COVID-19 vaccination in IBD patients and healthy controls (HCs).

RESULTS

1076 patients with IBD and 1126 HCs were analyzed. Seropositivity for anti-SARS-CoV-2 IgG was reported for most IBD patients, even if with a lesser rate compared with HCs (92.1% vs. 97.9%; p<0.001). HCs had higher antibody concentrations (median OD 8.72 [IQR 5.2-14-2]) compared to the whole cohort of IBD patients (median OD 1.54 [IQR 0.8-3.6]; p<0.001) and the subgroup of IBD patients (n=280) without any treatment or on aminosalicylates only (median OD 1.72 [IQR 1.0-4.1]; p<0.001).

CONCLUSIONS

Although most IBD patients showed seropositivity after COVID-19 vaccines, the magnitude of the humoral response was significantly lower than in HCs. Differently from other studies, these findings seem to be mostly unrelated to the use of immune-modifying treatments (ClinicalTrials.govID:NCT04769258).

Neutralizing Antibody Response, Safety, and Efficacy of mRNA COVID-19 Vaccines in Pediatric Patients with Inflammatory Bowel Disease: A Prospective Multicenter Case-Control Study

The vaccination of immunocompromised children against coronavirus disease 2019 is an important public health issue. We evaluated the serological response, safety, and efficacy of the BNT162b2 vaccine in children with and without inflammatory bowel disease (IBD). A prospective, multicenter, case–control study was conducted in a pediatric population, including patients with IBD, aged 12–18 years. Clinical characteristics, safety profile, and serum samples for surrogate virus-neutralizing antibody testing pre- and post-BNT162b2 vaccination were assessed. The breakthrough infection rate during the Omicron outbreak was calculated to evaluate efficacy. Fifteen controls and twenty-three patients with IBD were enrolled. After two vaccine doses, the median level of percentage inhibition was highly increased, without significant differences between the groups (control 96.9 and IBD 96.3). However, it was significantly reduced in IBD patients receiving combination therapy (anti-tumor necrosis factor-α + immunomodulators) relative to those in other therapies and controls. Serious adverse events were not observed. The breakthrough infection rate was 42.1%, without statistical differences between the groups. Immunization with BNT162b2 in patients with IBD was comparable with that in healthy adolescents in terms of immunogenicity and safety. Nevertheless, the efficacy of BNT162b2 in preventing infection caused by the Omicron variant in the pediatric population was insufficient.

Editorial: COVID-19 vaccines are safe and effective in patients with inflammatory bowel disease-but many unanswered questions remain

This article is linked to Bhurwal et al papers. To view these articles, visit https://doi.org/10.1111/apt.16913 and https://doi.org/10.1111/apt.16935

Editorial: COVID-19 vaccines are safe and effective in patients with inflammatory bowel disease-but many unanswered questions remain. Authors' reply

This article is linked to Bhurwal et al papers. To view these articles, visit https://doi.org/10.1111/apt.16913 and https://doi.org/10.1111/apt.16935

Vaccination for the Prevention of Infection among Immunocompromised Patients: A Concise Review of Recent Systematic Reviews

Vaccination is crucial for avoiding infection-associated morbidity and mortality among immunocompromised patients. However, immunocompromised patients respond less well to vaccinations compared to healthy people, and little is known about the relative efficacy of various vaccines among different immunocompromised states. A total of 54 systematic reviews (22 COVID-19; 32 non-COVID-19) published within the last 5 years in Pubmed® were reviewed. They demonstrated similar patterns within three seroconversion response categories: good (about >60% when compared to healthy controls), intermediate (~40−60%), and poor (about <40%). Good vaccine responses would be expected for patients with chronic kidney disease, human immunodeficiency virus infection (normal CD4 counts), immune-mediated inflammatory diseases, post-splenectomy states, and solid tumors. Intermediate vaccine responses would be expected for patients with anti-cytotoxic T-lymphocyte antigen-4 therapy, hematologic cancer, and human immunodeficiency virus infection (low CD4 counts). Poor vaccine responses would be expected for patients with B-cell-depleting agents (e.g., anti-CD20 therapy), hematopoietic stem-cell transplant, solid organ transplant, and liver cirrhosis. For all vaccine response categories, vaccination should be timed when patients are least immunosuppressed. For the intermediate and poor vaccine response categories, high-dose vaccine, revaccination when patients are less immunosuppressed, checking for seroconversion, additional booster doses, and long-acting monoclonal antibodies may be considered, supplemented by shielding measures.