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 Table of Contents  
Year : 2022  |  Volume : 14  |  Issue : 5  |  Page : 196-199  

COVID infections breakthrough post-vaccination: Systematic review

1 Department of Periodontics and Community Dentistry, Dr. Ziauddin Ahmed Dental College and Hospital, Aligarh Muslim University, Aligarh, UP, India
2 Department of Public Health Dentistry, Government Dental College, Dibrugarh, Assam, India
3 Department of Public Health Dentistry, I.T.S. Dental College, Muradnagar, Ghaziabad, UP, India
4 Executive MHA Student, IIHMR University, Jaipur, Rajasthan, India
5 General Dentist, 7 Days Family Dental, Indianapolis, IN, USA
6 Vishwanth Katti Institute of Dental Sciences, KLE Belgaum, India
7 MPH Student, Parul Univeristy, Limda, Waghodia, Vadodara, Gujarat, India

Date of Submission26-Jan-2022
Date of Decision30-Jan-2022
Date of Acceptance28-Feb-2022
Date of Web Publication13-Jul-2022

Correspondence Address:
Heena Dixit Tiwari
Parul Univeristy, Limda, Waghodia, Vadodara, Gujrat
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpbs.jpbs_132_22

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Introduction: Many new variants of the coronavirus are infecting the already vaccinated people. There have been reports of deaths also among the already vaccinated subjects. Hence, we conducted a systematic review and meta-analysis of the infection breakthrough after COVID vaccination. Materials and Methods: We piloted a review of the healthcare workers who completed the vaccination for COVID. The data were collected from the online resources for the breakthrough infections after vaccination. We then enumerated those subjects who had a breakthrough infection post-vaccination. The data collected were meta-analyzed for the incidence of the infection among the vaccinated individuals. Results: We observed that among nearly 2.3 lakh subjects, less than 3% were infected with the various new strains of the virus. The ratio of the breakthrough infection was different for the vaccinated (1.2%) and the partially vaccinated (3.2%) individuals with greater infection among the partially infected individuals. Discussion: The breakthrough infections are very low among vaccinated individuals and even lower among fully vaccinated individuals. Hence, vaccination is highly recommended to prevent the loss of life.

Keywords: Breakthrough infections, coronavirus, vaccines

How to cite this article:
Ali SA, Bhattacharyya S, Ahmad FN, Tiwari RV, Jain T, Baad SR, Tiwari HD. COVID infections breakthrough post-vaccination: Systematic review. J Pharm Bioall Sci 2022;14, Suppl S1:196-9

How to cite this URL:
Ali SA, Bhattacharyya S, Ahmad FN, Tiwari RV, Jain T, Baad SR, Tiwari HD. COVID infections breakthrough post-vaccination: Systematic review. J Pharm Bioall Sci [serial online] 2022 [cited 2022 Aug 9];14, Suppl S1:196-9. Available from:

   Introduction Top

The world has to endure so much loss due to the COVID pandemic. Vaccination drives have been conducted across the countries at a great speed.[1],[2],[3],[4] The desire and the need to get vaccinated among different countries is different. Though the world health authorities are urging to get vaccinated, many people are apprehensive of the vaccination. Some countries are even against vaccination drives. The most affected of the people during this pandemic was the healthcare workers. They were the most infected and had the highest death rates compared to other workforces. Because they were more prone to get infected due to continuous exposure, the vaccination was also given to them at a larger scale than the other groups. In the recent few months, breakthrough infections have been commonly reported among vaccinated individuals also.[5],[6],[7],[8],[9],[10] The data available vary among different populations with reinfections.[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18] Hence, we conducted a systematic review and meta-analysis of infections breakthrough after COVID vaccination among healthcare workers.

   Materials and Methods Top

We piloted a systematic review and meta-analysis among individuals who were vaccinated for the infection with coronavirus and had the breakthrough infection after the vaccination. The data were collected from online resources including PubMed, Medline, and Embase. We included original studies based on the Preferred Reporting Items for Systematic reviews and Meta analyses guidelines, the subjects were healthcare workers, the articles were in English, the subjects received vaccinations and reported breakthrough infections. We excluded case reports and reviews. The data thus collected were subjected to meta-analysis for the completion of vaccination (full/partial), the incidence of the breakthrough infection of the coronavirus among the various vaccinated groups, and the percentage hospitalized; the mortality rates were also calculated using the “Comprehensive Meta-Analysis (CMA) software, version 3 (BioStat, Englewood, NJ)” [Figure 1].
Figure 1: Comparisons of various vaccinated individuals for breakthrough infections

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   Results Top

We finalized 18 studies from across the world[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18] that fully filled all the inclusion criteria, with 2,30,000 healthcare workers as shown in the flow chart. All studies were of high quality based on the “New-Castle Ottawa Scoring System.” The ratio of the vaccinated and the non-vaccinated individuals was 16.4:1, whereas the ratio of the fully vaccinated to partially vaccinated individuals was 1.12:1. When the meta-analysis was performed, we observed that 2.145% of individuals had a breakthrough infection. Among them, partially and fully vaccinated individuals were 3.2% and 1.2%, respectively. Only 2.4% required hospital admission, and the death rate was 1.0%. We found no publication bias in our study where the “Egger's 2-tailed P value” was 0.4 [Figure 2].
Figure 2: Flow chart for the selection of studies

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   Discussion Top

The present study is one of the first to review the breakthrough infection among vaccinated healthcare workers. Our findings suggest that the incidence of breakthrough infections was as low as less than 3%.[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18] The incidence of the infection was even lower for those who were fully vaccinated. The healthcare workers while serving the patients may act as spreaders if they are not vaccinated. Hence, vaccinating these workforces is of prime significance. Though the acceptance of the vaccine varies greatly among the common public, we observed that almost all healthcare workers were vaccinated. In our study, partially and fully vaccinated individuals were compared and we observed that partially vaccinated subjects were more prone to infection than fully vaccinated subjects.[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18] We also observed that the ratio of hospitalization and mortality was also similarly distributed. Our findings are comparable to other studies that were conducted in the general public.[19],[20]

The limitations of our study were that we included only healthcare workers and compared the vaccinated individuals. Hence, the ratio of infections presented in our study may not be compared to general populations. Furthermore, we did not consider the type of vaccine administered.

   Conclusion Top

Within the limitations of our study, we can conclude that vaccinated individuals have a lower infection rate, and even if they were reinfected, they have lower hospital admission and death rates. Further comparative studies are suggested to corroborate our findings.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Amit S, Beni SA, Biber A, Grinberg A, Leshem E, Regev-Yochay G. Postvaccination COVID-19 among healthcare workers, Israel. Emerg Infect Dis 2021;27:1220-2.  Back to cited text no. 1
Angel Y, Spitzer A, Henig O, Saiag E, Sprecher E, Padova H, et al. Association between vaccination with BNT162b2 and incidence of symptomatic and asymptomatic SARS-CoV-2 infections among health care workers. JAMA 2021;325:2457-65.  Back to cited text no. 2
Azamgarhi T, Hodgkinson M, Shah A, Skinner JA, Hauptmannova I, Briggs TWR, et al. BNT162b2 vaccine uptake and effectiveness in UK healthcare workers–A single centre cohort study. Nat Commun 2021;12:3698.  Back to cited text no. 3
Bouton TC, Lodi S, Turcinovic J, Weber SE, Quinn E, Korn C, et al. COVID-19 vaccine impact on rates of SARS-CoV-2 cases and post vaccination strain sequences among healthcare workers at an urban academic medical center: A prospective cohort study. medRxiv 2021;2021.03.30.21254655. doi: 10.1101/2021.03.30.21254655.  Back to cited text no. 4
Cucunawangsih C, Wijaya RS, Lugito NPH, Suriapranata I. Post-vaccination cases of COVID-19 among healthcare workers at Siloam Teaching Hospital, Indonesia. Int J Infect Dis 2021;107:268-70.  Back to cited text no. 5
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Issac A, Kochuparambil JJ, Elizabeth L. SARS-CoV-2 breakthrough infections among the healthcare workers post-vaccination with ChAdO×1 nCoV-19 vaccine in the South Indian State of Kerala. medRxiv 2021:2021.08.07.21261587.  Back to cited text no. 7
Jacobson KB, Pinsky BA, Montez Rath ME, et al. Post-vaccination SARS-CoV-2 infections and incidence of presumptive B.1.427/B.1.429 variant among healthcare personnel at a northern California academic medical center. Clin Infect Dis 2021;ciab554. doi: 10.1093/cid/ciab554.  Back to cited text no. 8
Keehner J, Horton LE, Pfeffer MA, Longhurst CA, Schooley RT, Currier JS, et al. SARS-CoV-2 infection after vaccination in health care workers in California. N Engl J Med 2021;384:1774-5.  Back to cited text no. 9
Maroof S, Bakht N, Saleem S, Nisar S, Rashid Z, Mansoor E, et al. Covid-19 vaccine breakthrough infections among health care workers in military institutes of pakistan–till 30th june 2021. PAFMJ 2021;71:1471-5.  Back to cited text no. 10
Mathema B, Chen L, Chow KF, Zhao Y, Zody MC, Mediavilla JR, et al. Postvaccination SARS-COV-2 among health care workers in new jersey: A genomic epidemiological study. Microbiol Spectr 2021;9:e0188221.  Back to cited text no. 11
North CM, Barczak A, Goldstein RH, Healy BC, Finkelstein DM, Ding DD, et al. Determining the incidence of asymptomatic SARS-CoV-2 among early recipients of COVID-19 vaccines: A prospective cohort study of healthcare workers before, during and after vaccination [DISCOVER-COVID-19]. Clin Infect Dis 2021;ciab643. doi: 10.1093/cid/ciab643.  Back to cited text no. 12
Pandurangaiah R, Jose M. Post vaccination COVID-19 infection among health care workers in secondary medical care centre. Int J Clin Obstetr Gynaecol 2021;5:163-5.  Back to cited text no. 13
Sabnis R, Patil A, Shete N, Rastogi AK. Break-through COVID-19 infection rate with Indian strain in single-center healthcare workers – A real world data. medRxiv 2021. doi: 10.1101/2021.07.02.21258881.  Back to cited text no. 14
Sharma P, Mishra S, Basu S, Tanwar N, Kumar R. Breakthrough infection with SARS-CoV-2 and its predictors among healthcare workers in a medical college and hospital complex in Delhi, India. medRxiv 2021. doi: 10.1101/2021.06.07.21258447.  Back to cited text no. 15
Tang L, Hijano DR, Gaur AH, Geiger TL, Neufeld EJ, Hoffman JM, et al. Asymptomatic and symptomatic SARS-CoV-2 infections after BNT162b2 vaccination in a routinely screened workforce. JAMA 2021;325:2500-2.  Back to cited text no. 16
Tyagi K, Ghosh A, Nair D, Dutta K, Bhandari PS, Ansari IA, et al. Breakthrough COVID19 infections after vaccinations in healthcare and other workers in a chronic care medical facility in New Delhi, India. Diabetes Metab Syndr 2021;15:1007-8.  Back to cited text no. 17
Vaishya R, Sibal A, Malani A, Kar S, Prasad K H, Sv K, et al. Symptomatic post-vaccination SARS-CoV-2 infections in healthcare workers- A multicenter cohort study. Diabetes Metab Syndr. 2021 Nov-Dec;15(6):102306. doi: 10.1016/j.dsx.2021.102306. Epub 2021 Oct 4. PMID: 34619430; PMCID: PMC8489275.  Back to cited text no. 18
Malhotra S, Mani K, Lodha R, Bakhshi S, Mathur VP, Gupta P, et al. SARS-CoV-2 reinfection rate and estimated effectiveness of the inactivated whole virion vaccine BBV152 against reinfection among health care workers in New Delhi, India. JAMA Netw Open 2022;5:e2142210.  Back to cited text no. 19
Cohen JI, Burbelo PD. Reinfection with SARS-CoV-2: Implications for vaccines. Clin Infect Dis 2021;73:e4223-8.  Back to cited text no. 20


  [Figure 1], [Figure 2]


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