COVID Infections Breakthrough Post-Vaccination: Systematic Review

Abstract

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.

INTRODUCTION

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

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

RESULTS

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

DISCUSSION

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

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

Nil.

Conflicts of interest

There are no conflicts of interest.