Open Access
CC BY-NC-ND 4.0 · Journal of Gastrointestinal Infections 2022; 12(01): 018-028
DOI: 10.1055/s-0042-1757541
Review Article

Systematic Review and Meta-Analysis: Seroprevalence, Vaccination Rates, and Response for Hepatitis A in Inflammatory Bowel Disease

1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
,
1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
,
1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
,
Ritin Mohindra
2   Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
,
Praveen Kumar-M
3   Nference Lab, India
,
4   Department of Gastroenterology, Asian Institute of Gastroenterology, Chandigarh, India
,
Amol Patil
5   Department of Pharmacology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
,
Vikas Suri
2   Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
,
1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
› Author Affiliations

Funding None.
 


Abstract

Introduction Guidelines recommend hepatitis A virus (HAV) vaccination in individuals with inflammatory bowel disease (IBD). We performed a systematic review to inform the clinical practice regarding this guidance.

Methods After a PubMed and Embase search, duplicates were removed and the remaining titles screened for studies reporting relevant outcomes. Pooled seroprevalence rates for HAV, pooled vaccination rates, and pooled seroconversion rates were calculated. We also calculated pooled relative risk of seroprevalence for HAV among IBD and control population. Heterogeneity was investigated using subgroup analysis.

Results The pooled seroprevalence of HAV antibodies in patients with IBD (14 studies, 2,370 patients) was 0.36 (95% confidence interval [CI]: 0.22–0.53, I 2 = 95%). On comparing the seroprevalence of HAV in IBD with controls (4 studies), the pooled relative risk was not different between the two (0.94, 95% CI: 0.66–1.34, I 2 = 76%). The pooled seroconversion rate after two doses of HAV vaccination (5 studies, 221 patients) was 0.93 (95% CI: 0.88–0.96, I 2 = 0%). Three studies (104 patients) reported on the seroconversion after a single dose of HAV vaccination and the pooled seroconversion rate was 0.47 (95% CI: 0.35–0.59, I 2 = 20%). The pooled vaccination rate for hepatitis A among patients with IBD (18 studies, 9,521 patients) was 0.21 (95% CI: 0.14–0.30, I 2 = 99%).

Conclusion Hepatitis A vaccine has good immunogenicity in patients with IBD. The decision to routinely vaccinate IBD patients may be made in light of underlying seroprevalence of HAV.


Introduction

The management of inflammatory bowel disease (IBD) has many complex issues which need to be tackled by the clinicians. IBD not only involves the gastrointestinal system but may have extraintestinal manifestations. Liver disease in patients with IBD may be related to the extraintestinal manifestations, adverse effects of various therapies, or as a consequence of underlying viral infections which may flare due to use of immunosuppression.[1] Around 5% of IBD patients may have underlying hepatobiliary disease while a third could have derangements in liver function tests.[1] [2] Therefore, any strategy which is effective in preventing hepatic morbidity in these patients should be implemented. Vaccination is an effective strategy for prevention of hepatitis A virus (HAV) and hepatitis B virus (HBV) and has been recommended for IBD patients by various guideline panels.[3] [4] [5]

The need for vaccination with respect to HBV is unequivocal since the disease is associated with chronic liver disease and may eventually lead to hepatocellular carcinoma. However, there are several arguments for or against the strategy of routine vaccination for hepatitis A in patients with IBD. HAV typically causes a self-limiting disease and the occurrence of adverse outcomes like acute liver failure is relatively rare in childhood.[6] Further, childhood infection is common in many regions of the world and this provides an immunity against further infections during adulthood.[7] On the contrary, infection in adults may be associated with more risk of adverse outcomes and the childhood infection rates may be much lower in certain countries especially the Western world.[8] Further, patients with IBD may avoid eating out and be more likely to have safer eating habits leading to lesser likelihood of exposure to HAV infection. Therefore, the acquisition of infection in adulthood with possible underlying immunosuppression (disease or therapy related) and the presence of underlying liver disease in a subset may predispose to more adverse outcomes in patients with IBD.

Therefore, we conducted a systematic review to inform the clinical practices in relation to HAV vaccination in patients with IBD. We assessed the overall seroprevalence of HAV in patients with IBD, seroconversion after HAV vaccination in patients with IBD, and the uptake of HAV vaccination in patients with IBD.


Methods

We followed the guidance provided in the Meta-analysis Of Observational Studies in Epidemiology statement for the present systematic review.[9]

Database Search

We searched PubMed and Embase from inception till September 11, 2021. The keywords used were hepatitis A, inflammatory bowel disease or ulcerative colitis (UC) or Crohn's disease (CD), and vaccination combined with the operator AND. [Supplementary Table S1] (available in the online version) shows the detailed search strategy used for this systematic review. We searched for additional papers from the references of these studies. After combining the results, the duplicates were manually removed. The remaining results underwent initial screening for titles and abstracts to identify papers eligible for the full-text screening by two reviewers (V.S., P.B.). The differences were resolved by discussion among the reviewers.


Study Selection

We included studies which provided information regarding baseline seroprevalence rates of previous HAV infections with IBD, the vaccination rates for HAV in patients with IBD, and the seroconversion rates after HAV vaccination (single and double dose) in patients with HAV vaccination. These reports were included irrespective of language, geographic, or age-related restrictions or the type of publications. For vaccination rates we included all reports irrespective of the manner in which this was estimated (records, questionnaires, or Internet-based surveys). However, physician surveys intended to evaluate the practices regarding vaccination were not included. We excluded studies where there was suspicion of duplication of data (same center with multiple reports from overlapping time periods). For any analysis we excluded a study if the total population reported was less than 10 patients. The studies were excluded if they did not provide relevant information or if the data was not extractable.


Data Extraction

The data were extracted on a preformat and included the details regarding the study duration, region, and study population (IBD, CD, and UC; adult or pediatric; any specific population, e.g., pregnancy or postpartum). The details of study (retrospective, prospective, trial) were also extracted.


Outcomes

The outcomes of interest relevant to the systematic review for which data were extracted included:

  1. Seroprevalence of HAV infection in IBD population. The data were also extracted for UC and CD separately to compare the seroprevalence rates in these two groups. The data from controls/healthy population was also extracted when available.

  1. The seroconversion after HAV vaccination after one and two doses of vaccine was also extracted.

  1. The vaccination rates of IBD patients for HAV were also extracted and the method of estimating vaccination rates was also extracted (survey or records).


Analysis

Apart from the base package of the R statistical software version 4.0.1, meta and metafor packages were also utilized for the analysis.[10] [11] We used the random effect model with inverse variance approach to calculate pooled seroconversion rates after HAV vaccination. The individual seroconversion/seroprevalence/vaccination rates were logit transformed prior to pooling. The seroprevalence rates between the IBD population and control population were compared using pooled relative risk obtained by the Mantel–Haenszel method. I 2 and p-values were used for the assessment of heterogeneity. Subgroup analysis, where feasible, were performed to address and investigate any significant heterogeneity (I 2 > 50%). Baujat plot was also constructed to identify any specific studies contributing to the heterogeneity.


Methodological Quality and Risk of Bias Assessment

The publication bias was assessed by the visual assessment of the funnel plot (if studies > 10). Also, the Egger test was conducted to identify the publication bias. Two investigators (A.J. and P.B.) separately and independently assessed the methodological quality and risk of bias for each study using the Joanna Briggs Institute critical appraisal tool for prevalence studies.[12] Any disagreement was resolved by mutual consensus after discussion with V.S.



Results

Study Selection

We identified 444 records after PubMed and Embase search. After removing duplicates, 349 records were eligible for title and abstract screening. Three hundred and two titles were excluded for various reasons ([Fig. 1]). Of the 47 titles assessed for full-text screening, 10 were excluded for various reasons ([Supplementary Table S2], available in the online version),[13] [14] [15] [16] [17] [18] [19] [20] [21] [22] and eventually 37 papers were included in the systematic review. Fourteen studies were included in the analysis about baseline seroprevalence of hepatitis A in the setting of IBD,[23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] 5 studies reported on the seroconversion after complete HAV vaccination,[26] [37] [38] [39] [40] while 18 studies reported about the HAV vaccination rates in IBD patients[30] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] ([Tables 1] [2] [3]).

Zoom
Fig. 1 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart showing the selection of studies for the systematic review.
Table 1

The studies reporting the seroprevalence of HAV the details regarding patients, vaccinations, and outcomes

Reference

Region

Study period

Study type

Patient population

Adult/Pediatric

Age

Male gender

Definition of seropositivity

1

Hong et al 2022

South Korea

January 2016 and December 2018

Cohort

263 IBD

Adult

30 years (IQR, 22 to 46)

167 [67.3%]

anti-HAV IgG ≥ 20 U/mL

2

Kalra et al 2021

India

August 2015 to October 2016

Case–Control

41 CD

Adult

33.5 (median)

27 [65.8%]

IgG anti- HAV antibody

3

Ruiz-Cuesta et al 2016

Spain

January and March 2012

Cohort

153 IBD, 77 UC, 76 CD

Adult

43.30 ± 14.19

69 [45.1%]

Prevaccination serological testing

4

Urganci and Kalyoncu 2013

Turkey

2000 and 2012

Case–Control

47 IBD, 25 UC, 14 CD, 8 IBDU

Pediatric

11.06 ± 3.74

25 [53.2%]

Prevaccination serological testing

5

Hafner et al 2008

Germany

July 1999 and May 2003

Case–Control

121 IBD, 73 CD, 48 UC

Adult

36.8 ± 10.5

65 [53.7%]

HAV titers greater than 10 IU/L

6

Melmed et al 2006

United States

2004–2005

Cohort

16 of 169 IBD patients with serostatus for HAV

Adult

NA

NA

Detectable anti-HAV antibody

7

Feeney et al 2002

United Kingdom

Case–Control

137 UC, 139 CD

Adult

NA

NA

Hepatitis A IgG status

8

Moon and Moon 2021

United States

2009–2010

Retrospective analysis of NHANES

55 IBD patients and 4,443 non-IBD

Adult

NA

NA

Hepatitis A seropositivity

9

Shao et al 2015

Australia

March–May 2015

Retrospective audit and prospective survey

150 IBD patients screened for HAV

Adult

NA

NA

NA

10

Moreira Goncalves et al 2015

Portugal

NA

Prospective study

139 patients, 68 UC, 71 CD

Adult

NA

53 [38.1%]

?serologic status

11

Morace et al 2013

Italy

NA

Questionnaire and serology

192 IBD

Adult

51 years

94 [48.9%]

Serology

12

Riestra et al 2013

Spain

September 2011 to October 2012

Prospective study

787 IBD, 467 CD, 293 UC, 27 unclassified

Adult

44.3 years

357 [45.4%]

Serological status

13

De Bruyn et al 2012

Canada

September 2011–August 2012

Cross-sectional

156 IBD, 93 CD, 37 UC, 16 unclassified

Pediatric

NA

NA

Positive detection of HAV IgG

14

Alkhouri et al 2010

United States

NA

Cohort

100 IBD, 91 CD, 9 UC

Pediatric

NA

60 [60%]

Serology HAV IgG

Abbreviations: CD, Crohn's disease; HAV, hepatitis A virus; IBD, inflammatory bowel disease; IBDU, inflammatory bowel disease unclassified; IgG, immunoglobulin G; IQR, interquartile range; NA, not available; NHANES, National Health and Nutrition Examination Survey; UC, ulcerative colitis.


Table 2

Studies reporting seroconversion after HAV vaccination

Reference

Region

Study period

Study type

Patient population

Adult/Pediatric

Age

Male gender

Dosage

Response

1

Urganci and Kalyoncu 2013

Turkey

2000–2012

Prospective

47 IBD, 25 UC, 14 CD, 8 indeterminate

23 received vaccine

Pediatric

11.06 ± 3.74

25 [53.2]

720 milliELISA units of inactivated hepatitis A virus vaccine (HAV) (0 and 6 months)

anti-HAV IgG

2

Moses et al 2011

United States

NA

Prospective

12 IBD patients on infliximab

Pediatric

18.3 years

8 [66.6%]

710 milliELISA units at 0 and 6 months or double (if age > 19 years)

anti-HAV IgG

3

Radzikowski et al 2011

Poland

October 2006 and August 2009

Prospective

66 adolescents and children with IBD

Pediatric

13.61 ± 0.4

33 [50%]

Two doses of HAV in a 6- to 12-month interval

Seroconversion at 12 weeks after 2nd dose (> 20 IU/mL)

4

Dimas et al 2019

Greece

NA

Prospective

356 IBD patients

90 got two doses

21 got single dose

Adult

50.0 [33.5–63.1]

NA

1 mL, two doses, one at baseline and the second 6–12 months after the first dose

Positive anti-HAV IgG > 3 months after 2nd dose

5

Karmiris et al 2014

Greece

NA

Prospective

167 IBD patients, only 43 were eligible for vaccination

Adult

45.4 [30.3–60.3]

103 [61.7%]

Havrix, 1 mL, two doses, 0 and 6–12 months

anti-HAV IgG > 20 mIU/mL

Abbreviations: CD, Crohn's disease; HAV, hepatitis A virus; IBD, inflammatory bowel disease; IgG, immunoglobulin G; NA, not available; UC, ulcerative colitis.


Table 3

Studies reporting the vaccination rates for HAV in patients with inflammatory bowel disease

1

Pittet et al 2021

Switzerland

Cross-sectional study

306 IBD

Adults

Median 42.7

Using questionnaire, immunization records review

2

Chiarella-Redfern et al 2022

Canada

September 2012–December 2018

Retrospective cohort study

303 pregnant IBD

Pregnancy

31.24

0

Vaccine records

3

García-Serrano et al 2020

Spain

Records until December 2016

Cross-sectional, retrospective study

1,722 IBD

Adults

NA

866 [50.3%]

Online records

4

Mao et al 2019

USA

2007 onwards

Prospective national registry

628 IBD pregnant

Adults

Questionnaire

5

Pham et al 2018

USA

2010 and 2013

Retrospective cohort study

1,401 IBD on anti-TNF therapy

Adults

40.6 ± 16.8

668 [48.4%]

Electronic database

6

Malhi et al 2015

Canada

September 1, 2013 and January 31, 2014

Patient survey

300 IBD

Adults

35.4 ± 13.2

146 [48.7%]

Patient Survey

7

Yun et al 2013

South Korea

November 2011 to February 2012

Questionnaire survey

192 IBD

Adults

39.7

121 [63.0%]

Patient survey

8

Moon and Moon 2021

USA

2009–2010

Retrospective analysis of NHANES

48 IBD

Adults

NA

NA

NHANES data

9

Hussain et al 2020

USA

March 1, 2019 to December 31, 2019

Retrospective study

356 IBD

Adults

NA

172 [48.3]

Two IBD clinics electronic checklist

10

Strasse et al 2019

Brasil

July 2015 to June 2016

Questionnaire survey

239 IBD

Adults

46.4 ± 12.7

87 [36.4]

Patient survey

11

Kowalska-Duplaga et al 2019

Poland

September 2015 and September 2016

Prospective study

214 children IBD

Children

14.5 (11.5–16.0)

117 [54.7%]

Review of immunization cards

12

Kakati et al 2018

USA

2016

Retrospective charts

210 IBD

Adults

NA

NA

Review of charts

13

Waszczuk et al 2018

Poland

NA

Self-completed patient survey

195 IBD

Adults

37 ± 15

98 [50.2%]

Patient survey

14

Vellanki et al 2018

USA

January 1, 2007 to December 31, 2016

Retrospective data review

1396 IBD

Adults

NA

NA

Database review

15

Ryu et al 2010

South Korea

November 2013 and February 2015

Questionnaire survey

287 IBD

Adults

29 years (range, 16–69)

188 [67.6%]

Questionnaire

16

Love et al 2012

USA

44-month period

Retrospective

24 IBD on anti-TNF

Adults

NA

NA

Electronic records

17

Xu et al 2019

USA

2015–2016

National Health Interview Survey

951 IBD

Adults

NA

360 [37.9]

Patient survey

18

Wasan et al 2012

USA

NA

Prospective Internet patient survey

958 IBD

Adults

45 (IQR 31–57)

260 [27.2%]

Internet-based survey

Abbreviations: HAV, hepatitis A virus; IBD, inflammatory bowel disease; IQR, interquartile range; NA, not available; NHANES, National Health and Nutrition Examination Survey, TNF, tumor necrosis factor.



Seroprevalence of Hepatitis A in Inflammatory Bowel Disease

The pooled seroprevalence of HAV antibodies in patients with IBD on the basis of 14 included studies (2,370 patients) was 0.36 (95% confidence interval [CI]: 0.22–0.53, I 2 = 95%) ([Fig. 2]). To explain the high degree of heterogeneity we performed a subgroup analysis on the basis of factors which are likely to impact the underlying seroprevalence, that is, age of included population and the region of the studies. As expected, the seroprevalence was higher in adults (0.42, 95% CI: 0.27–0.59, I 2 = 95%) as compared with the pediatric studies (0.18, 95% CI: 0.04–0.55, I 2 = 94%), however, the heterogeneity was high ([Supplementary Fig. S1], available in the online version). Regional differences were apparent with studies from Asia reporting highest seroprevalence rates and those from North America reporting the lowest seroprevalence rates but the heterogeneity even among various region-based groups was high ([Supplementary Fig. S2], available in the online version). Baujat plot could identify two studies which contributed the maximum to the heterogeneity ([Supplementary Fig. S3], available in the online version). The sensitivity analysis by excluding the two studies which did not report the method to determine seroprevalence did not change the pooled seroprevalence rates (0.32, 0.19–0.49, I 2 = 95%) ([Supplementary Fig. S4], available in the online version). On comparing the seroprevalence of HAV in IBD as compared with controls, the pooled relative risk (4 studies) was not different between the two groups (0.94, 95% CI: 0.66–1.34, I 2 = 76%) ([Fig. 3]).

Zoom
Fig. 2 Forest plot depicting the pooled seroprevalence rates for hepatitis A virus (HAV) in patients with inflammatory bowel disease.
Zoom
Fig. 3 Pooled relative risk of seropositivity of hepatitis A virus (HAV) in patients with inflammatory bowel disease (IBD) as compared top controls.

Seroconversion after HAV Vaccination

There were five studies (221 patients, two in the pediatric age group) reporting response to two doses of hepatitis A vaccination in patients with IBD. The pooled seroconversion rate to two doses of HAV vaccination was 0.93 (95% CI: 0.88–0.96, I 2 = 0%) ([Fig. 4]). Three studies (104 patients) reported on the seroconversion after a single dose of HAV vaccination and the pooled seroconversion rate was 0.47 (95% CI: 0.35–0.59, I 2 = 20%) ([Supplementary Fig. S5], available in the online version).

Zoom
Fig. 4 Pooled seroconversion rates after two doses of hepatitis A virus (HAV) vaccination in patients with inflammatory bowel disease (IBD).

Vaccination Rates for Hepatitis A in Patients with IBD

The pooled vaccination rate for hepatitis A among patients with IBD (18 studies, 9,521 patients) was 0.21 (95% CI: 0.14–0.30, I 2 = 99%) ([Fig. 5]). To explain the heterogeneity, we performed subgroup analysis based on the region (continents) and the population (adults, pediatric, and pregnant). Interestingly, the HAV vaccination rates were highest among the pregnant population (0.56, 0.45–0.66, I 2 = 90%) as compared with adults (0.18, 012–0.27, I 2 = 98%) ([Supplementary Fig. S6], available in the online version). The vaccination rates were higher in the North American population (0.29, 0.19–0.41, I 2 = 99%) as compared with the other three continents ([Supplementary Fig. S7], available in the online version). A subgroup analysis on the basis of study type indicated that the vaccination rates in prospective studies was 0.37 (0.15–0.66, I 2 = 98%), in retrospective studies was 0.18 (0.09–0.33, I 2 = 99%), and in surveys was 0.19 (0.11–0.32, I 2 = 97%) ([Supplementary Fig. S8], available in the online version). Baujat plot identified three studies which had maximum contribution to heterogeneity ([Supplementary Fig. S9], available in the online version).

Zoom
Fig. 5 Pooled rates of vaccination for hepatitis A virus (HAV) in patients with inflammatory bowel disease (IBD).

Risk of Bias

For seroprevalence of HAV, both the funnel plot and the Egger test suggest absence of any publication bias ([Supplementary Fig. S10], available in the online version). The risk of bias analysis of studies included in the analysis of seroprevalence, seroconversion rates, and vaccination rates are shown in [Supplementary Tables S3]–[S5] (available in the online version), respectively. For pooled HAV vaccination rates in IBD of HAV, the visual analysis of the funnel plot and the Egger test suggest that publication bias is unlikely ([Supplementary Fig. S11], available in the online version). However, majority of studies were of low risk. Some of the studies available as abstracts could not be completely assessed for all domains.



Discussion

Hepatitis A vaccination is recommended for patients with IBD. However, it is unclear if the vaccination should be done routinely or after checking the presence of previous exposure. Also, in regions with high baseline seroprevalence, the utility of vaccination at the time of diagnosis is uncertain as many individuals may have been exposed to HAV in the past. The present systematic review provides evidence that the seroprevalence of hepatitis A infection is variable across the globe and the highest rates are found in Asia while North America may have the lowest rates. Importantly, the seroprevalence rates in the IBD population are similar to the controls, suggesting that the population level data can be used as a proxy indicator of seroprevalence in IBD patients and guide the testing/vaccination strategy. Further, the results suggest that the vaccination rates against hepatitis A are low across the globe. This is even true in North America where the baseline seroprevalence is low and the vaccination rates are higher as compared with other regions of the globe.

Usually, there is a concern about response to vaccination (like HBV and coronavirus disease 2019) in patients who are on certain drug therapies like immunomodulators and biologicals.[58] [59] Our analysis demonstrates that this may not be a significant concern with complete HAV vaccination although the data are limited. Four of the five included studies provided information about the underlying drugs used. While seroconversion was good with most drugs, one report suggested that seroresponse may be attenuated in those on anti-tumor necrosis factor.[39] Another study, however, suggested good response in the patients who were on infliximab.[37] This suggests that post-vaccination testing of seroconversion may not be required even in patients with underlying exposure to immunomodulators. The response to a single dose of vaccination is also fair and therefore, vaccination can be administered at the time of starting any immunosuppressive therapy.

Hepatitis A is an important cause of acute viral hepatitis in the world. It is a positive single-stranded ribonucleic acid virus belonging to the Picornaviridae family and primarily undergoes replication in hepatocytes. The risk factors of HAV infection include intravenous drug abuse, chronic liver disease, travel to endemic areas, occupational exposure, prisoners, older persons, and immunocompromised. The transmission is usually by feco-oral route while the virus is excreted in human bile and stool. With prolonged immunosuppression in patients of IBD, hepatitis A infection is a concern. Infection with hepatitis A can lead to acute viral hepatitis and acute liver failure.[6] Rarely hepatitis A infection can cause relapsing hepatitis and prolonged cholestasis. With vaccination available, hepatitis A-related liver disease is preventable in patients with IBD. Although this is the first systematic review on hepatitis A vaccination in IBD, there are certain limitations. We could not separately assess the effect of underlying disease (UC or CD), activity, and drug classes because of the limited number of studies. Further, the studies for a particular region regarding seroprevalence were limited and may not be directly applicable to the entire region.

In regions with low seroprevalence, a strategy to vaccinate without testing of prior exposure may be appropriate. However, in regions with high seroprevalence (100% in one study from India), the need for routine vaccination of all IBD patients is questionable.[24] However, with improvements in sanitation there may be decline in childhood exposure to HAV and changes in such policies may be needed with changing seroprevalence data. In this regard, the seroprevalence rates in the general population can guide the strategy because these are proxy indicators of seroprevalence of HAV in the IBD population. Further, increasing immigration rates bring their own challenges in making blanket policies for a particular region. The systematic review suggests that a single global policy for HAV vaccination may not be appropriate and the policy should be based on regional seroprevalence rates, cost of testing, and the cost of vaccination.



Conflict of Interest

None declared.

Acknowledgments

None.

Ethical Statement

Not applicable as there was no direct research on human or animals as the study is a systematic review of previously published literature.


Author Contributions

A.J.: Search, screening, RoB, draft, initial draft and approval. A.K.S.: RoB, approval. P.B.N., R.M., S.M.: Screening, approval. V.Suri, A.P., P.K.M.: Important intellectual content and approval. V.Sharma.: Conception, search, analysis, draft and revision.


Data Availability Statement

There is no data associated with this work and the data used are available in public domain.


Supplementary Material


Address for correspondence

Vishal Sharma, MD, DM
Department of Gastroenterology, Post Graduate Institute of Medical Education and Research
Chandigarh 160012
India   

Publication History

Received: 08 February 2022

Accepted: 25 May 2022

Article published online:
22 September 2023

© 2022. Gastroinstestinal Infection Society of India. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India


Zoom
Fig. 1 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart showing the selection of studies for the systematic review.
Zoom
Fig. 2 Forest plot depicting the pooled seroprevalence rates for hepatitis A virus (HAV) in patients with inflammatory bowel disease.
Zoom
Fig. 3 Pooled relative risk of seropositivity of hepatitis A virus (HAV) in patients with inflammatory bowel disease (IBD) as compared top controls.
Zoom
Fig. 4 Pooled seroconversion rates after two doses of hepatitis A virus (HAV) vaccination in patients with inflammatory bowel disease (IBD).
Zoom
Fig. 5 Pooled rates of vaccination for hepatitis A virus (HAV) in patients with inflammatory bowel disease (IBD).