General Section Original Article

Breakthrough infection after Covishield

COVID-19 vaccine among health care
workers at Patan Academy of Health
Sciences, Nepal
Jay Shah1 , Priscilla Samson2 , Nabees MS Pradhan3 , Ashis
Shrestha , Shreekrishna Maharjan5 , Shanta Dangol6 , Sarala KC7
4

1
Prof. Surgery, 3Prof. Orthopedics and Trauma surgery, 4Asst. Prof.
General Practice and Emergency Medicine, 5Assoc. Prof. Biochemistry and
ISSN: 2091-2749 (Print) Molecular Lab Medicine, 6Nursing Director, Patan Hospital, School of Medicine;
2Assoc. Prof., 7Prof. & Nursing Dean, Lalitpur Nursing Campus, School of Nursing
2091-2757 (Online)
and Midwifery; Patan Academy of Health Sciences, Lalitpur, Kathmandu, Nepal

Abstract

Correspondence Introduction: Coronavirus Disease 2019 (COVID-19) vaccines have an

Jay Shah important role in the control and prevention of the pandemic. However,
Dept. of Surgery, Patan infection after vaccination, though uncommon, has been reported after
Hospital, Patan Academy of
partial or complete immunization. This study aims to find out vaccine
Health Sciences, Lalitpur, Nepal
Email: drjaywufei@hotmail.com
breakthrough infection after the administration of the Covishield COVID-
drjaywufei@gmail.com 19 vaccine.

Method: This cross-sectional survey was conducted among the health care
Peer Reviewers workers (HCWs) from May 2021 to July 2021 at Patan Hospital, Patan
Prof. Madhusudan Subedi, Academy of Health Sciences, Nepal who received the Covishield vaccine.
Patan Academy of Health The data were collected using Google form and a printed questionnaire on
Sciences, Nepal COVID 19 breakthrough infection ≥2w after vaccination. The rate of
breakthrough infection, hospitalization, and its association with age,
Prof. Dr. Gehanath Baral, Nobel
Medical College, Biratnagar, gender, and working departments of HCWs was analyzed using SPSS.
Nepal Ethical approval was obtained.

Submitted Result: Out of 1462 HCWs approached, 880 completed the survey, among
21 Aug 2021 which 819(93.1%) had a completed vaccination status. Infection after the
first and before the second dose was 164(18.7% of 880) and after two
Accepted doses 131(16%). The breakthrough infection occurred in 83 (10.1% of 819).
30 Aug 2021 There was no statistically significant association of breakthrough infection
with age, gender, and working department of HCWs. Total 74(8.4%) were
How to cite this article managed by admission in hospital.
Jay Shah, Priscilla Samson,
Nabees MS Pradhan, Ashis Conclusion: The findings of this study reveal a low breakthrough infection
Shrestha, Shreekrishna rate after Covishield vaccination among HCWs at Patan Academy of Health
Maharjan, Shanta Dangol, et al. Sciences, Kathmandu, Nepal. Overall, COVID-19 infection rates decreased
Breakthrough infection after after the first and second dose of the vaccine.
Covishield COVID-19 vaccine
among health care workers at Keywords: Breakthrough infection, Covishield COVID-19 vaccine,
Patan Academy of Health
reinfection, Nepal
Sciences, Nepal. Journal of
Patan Academy of Health
Sciences. 2021Aug;8(2):10-17.

https://doi.org/10.3126/jpahs.
v8i2.28833

10 Journal of Patan Academy of Health Sciences. 2021Aug;8(2):10-17.

 Jay Shah: Breakthrough infection after COVID-19 vaccine

Introduction included an information sheet for proforma

and voluntary participation. Completion of the
There is a small percentage of re-infection of form was considered as consent. Data
COVID-19 (caused by coronavirus SARS-CoV-2), collection via print questionnaire was used for
and breakthrough infection after those participants who did not know how to
vaccination. COVID-19 vaccines help control
1,2
use an electronic device to fill the Google form.
the pandemic by preventing infection, The forms were distributed and collected
decreasing its severity and hospitalization.3,4 within two days. For data collection,
researchers from among the listed
A breakthrough infection after vaccination is investigators (authors) were designated to
the detection of SARS-CoV-2 RNA or antigen in cover the different departments of HCWs. Data
a respiratory specimen ≥14 d after collection required approximately 10 min of
vaccination.2 Breakthrough infections are mild participants’ time.
and occur in 0.03%-0.05%.5-7 Higher incidence
of 13.3% (15 out of 107) among health care The study variables included HCWs
workers (HCWs) was reported in Fortis, India.8 demographics (gender, age, departments),
Nepal began COVID-19 vaccination with number of vaccines (1st dose only or
Covishield first for health care workers on 27 recommended two doses), COVID-19 infection
Jan 2021.9 Effectiveness of a vaccine, and its after the vaccine, and the need for
equitable distribution is important to control hospitalization.
COVID-19.10
For sampling purposes, the participants were
This study aims to find out vaccine grouped as per discipline, for example, HCWs
breakthrough infection among HCWs of Patan medical (doctors, nurses, paramedical staff),
Academy of Health Sciences (PAHS), Nepal non-medical (administrative staff,
which will help in effective vaccine rollout and housekeeping staff, support staff, teaching
plans. faculties, and students). Teaching faculties
involved in clinical work were grouped as
medical; administrative staff included office
Method workers except for medical, paramedical,
support, teaching staff; support staff included
This was a cross-sectional study conducted housekeeping, security, driver, and other than
from May 2021 to Jul 2021 to find out paramedical, administrative, and teaching
breakthrough infection after the staff.
administration of Covishield (ChAdOx1 nCoV-
19 Corona Virus Vaccine of AstraZeneca The breakthrough infection after COVID-19
produced by Serum Institute of India) COVID- vaccination was defined as Polymerase Chain
19 vaccine among HCWs at PAHS in Reaction (PCR) positive in a respiratory
Kathmandu, Nepal. All HCWs from the main specimen ≥14 d after two doses of Covishield.7
teaching hospital (Patan Hospital) and 3- Infection that occurred <14 d of vaccination
schools (School of Medicine, Nursing and was categorized as an early breakthrough. The
midwifery, Public Health) of PAHS were PCR data were verified by one of the co-
included. A list of HCWs who received investigators from the laboratory at Patan
Covishield was obtained from the vaccination Hospital, PAHS.
record of PAHS. Head of Departments (HODs)
provided the email addresses of their staff for The Google form data were interpreted in
the survey. The HCWs who were not familiar Excel and analyzed by SPSS for frequencies and
with email were requested to provide their percentages, and the Chi-square test was used
phone numbers. for an association between age, gender,
working departments, and COVID-19 infection.
Data were collected via email (or social media
account Viber) using Google form (LINK) which

11 Journal of Patan Academy of Health Sciences. 2021Aug;8(2):10-17.

 Jay Shah: Breakthrough infection after COVID-19 vaccine

Data were collected after obtaining ethical researcher during data processing and
approval from the Institutional Review thereafter deposited with the institution as
Committee of PAHS (Ref: drs2105281528). required by the ethical committee/institution
Confidentiality was maintained by not sharing for storage of at least 5 y, accessible to the
the data for any purpose other than this ethical committee and/or executive
research. Data were saved in a password- committee when required.
protected file on a personal computer of the

Survey form sent out 1462 (Google form 1309; Print 153)

Response received=880 (60.1%) No

Google form 738, Print 142 582(39.9%)

Completed both doses of Covishield

Yes No
819(93.1%) 61(9.9%)

History of COVID-19 before

Infection after vaccine
vaccine

Yes No Yes No 688

215(8.8%) 604(96.1%) 131(16.0%) (86.0%)

Breakthrough infection
83(10.1%)
Figure 1. Flowchart of Covishield COVID-19 vaccine breakthrough infection survey among HCWs at PAHS,
Nepal

Result dose was 164(18.7% of 880); whereas after

both doses was 131(16.0% of 819), Table 2.
There were 880 participants (738 google
forms, 142 print forms) who completed the Demographic variables had no statistically
survey, a response rate of 60.2% (880 out of significant association with breakthrough
1462 approached). Google form response rate infections, Table 3. Out of 819 HCWs who
was 56.4%(738 replied of 1309), and print completed vaccination, 241(27.3%) had a
forms response was 92.8% (142 of 153). history of COVID-19 infection before the
vaccine, and out of these 215(89.2%)
Males were 194(22%). The majority of completed both doses of Covishield. Out of
participants 606(68.9%) were in the age group 639 who did not have COVID-19 infection prior
20-40 y. Medical HCWs (doctors, nurses, to vaccination 604(94.5%) completed both
paramedics) were 464(52.7%), non-medical doses of vaccine. Out of 215 who had infection
(administrative, teaching, support staff, and prior to vaccine 24(11.1%) had a breakthrough
students) 416(47.3%), Table 1. infection while out of 604 who did not have
Out of 880 HCWs, 819(93.1%) completed the infection prior to vaccine 58(9.6%) had a
recommended two doses of Covishield. breakthrough infection, the difference was
Infection after the 1st dose and before the 2nd statistically significant, Table 4. None required
ventilator support and mortality was nil.

12 Journal of Patan Academy of Health Sciences. 2021Aug;8(2):10-17.

 Jay Shah: Breakthrough infection after COVID-19 vaccine

Table 1. Demography HCWs at PAHS in Covishield COVID-19 vaccine breakthrough infection survey, N=880

Variable N %
Age in y <20 43 4.9
20-40 606 68.9
41-60 215 24.4
>60 16 1.8
Gender Male 194 22.0
Female 686 78.0
HCWs Medical Dr. 49 5.6
Nurse 350 39.8
Paramedics 65 7.4
HCWs Non-medical Administration 32 3.6
Teaching 35 4.0
Support 198 22.5
Student 151 17.2
Hospitalized 74 8.4
PCR confirmation, i.e., PCR positive 295 33.5
HCWs- health care workers (all the staff and students of PAHS/Patan Hospital, Nepal), PAHS- Patan Academy of Health
Sciences, Covishield- ChAdOx1 nCoV-19 Corona Virus Vaccine of AstraZeneca produced by Serum Institute of India

Table 2. COVID-19 infection after Covishield COVID-19 vaccine among HCWs at PAHS, Nepal

Infection after vaccination N %

After 1st dose* and before 2nd dose i.e. out of 880 164 18.7

After two doses, i.e. out of 819 131 16.0

Early breakthrough after complete vaccination <14 d 48 5.9
Breakthrough inf. after complete vaccination ≥14 d 83 10.1
*Took the first dose of the vaccine only 61, and 11 had an infection.

Table 3: Association of demographic variables for breakthrough infection (N=83) ≥14 d after Covishield
among HCWs at PAHS, Nepal
Variables Breakthrough infection, N=83 X2 value p value
Age ≤40y 60(72.3%) 0.086 0.770
Age >40y 23(27.7%)
Male 24(28.9%) 2.517 0.113
Female 59(71.8%)
Medical 44(53.0%) 0.000 0.991
Non-medical 39(47.0%)

Table 4. Comparison of reinfection in those who had COVID-19 infection before vaccination (Group A: N=215)
with those who did not (Group B: N=604) at PAHS, Nepal
Infection after vaccine Group A, prior infection before Group B, No prior infection before
vaccine (N=215), N, % vaccine (N=604), N, %
After 1st dose <14 d 58 26.9 22 3.6
≥14 d 39 18.1 33 5.5
After 2nd dose <14 d 23 10.7 23 3.8
≥14 d* 24 11.1 58 9.6
*breakthrough infection following complete vaccine, Chi Square statistics is 78.8, p value = <0.00001

13 Journal of Patan Academy of Health Sciences. 2021Aug;8(2):10-17.

 Jay Shah: Breakthrough infection after COVID-19 vaccine

Discussion We found 241(27.4%) HCWs had an infection

before vaccine rollout. The reinfection and
Our survey among HCWs at PAHS, Nepal breakthrough were higher in those who had
following the Covishield COVID-19 vaccine infection prior to the vaccination and the
revealed a breakthrough infection (≥14 d of breakthrough rate was also higher. One of the
complete vaccination) of 83(10.1%) confirmed studies has expressed COVID-19 infection to
by a PCR test. We did not find a statistically confer greater immunity than vaccine14, yet
significant difference in breakthrough another study has reported that with prior
infections among medical and non-medical natural infection of COVID-19, they were 4.5
HCWs. The breakthrough infection rate is times less likely to experience re-infection
higher than the generally reported of 0.03% to even after partial vaccination.4 This was
0.05%5,6,7,11 and lower than 13.3%(15/107) however not seen in our study as we did not
from Fortis, India.8 The Fortis report was after monitor antibody levels in those who reported
completion of vaccination (1/3rd received being infected prior to vaccination, and we did
Covaxin and 2/3rd Covishield) among HCWs not evaluate the period of infection before
(doctors, nurses, paramedical workers, and vaccination. It has been observed that IgG
other staff). Such a high rate of breakthrough antibody peaks approximately after 25 days of
infection could be due to virus variants, and infection and remains detectable for at least
the lack of further analysis separately for 120 days of infection.15 In our study, the rate of
Covaxin and Covishield. Breakthrough infection decreased with subsequent
infection among HCWs was 0.97% to 1.19% in vaccination, conferring the development of
California USA.5 The breakthrough infection in herd immunity. The development of herd
the real world scenario during mass immunity has been demonstrated in several
vaccination has been higher than (0.05%) studies, even in cases of mild infection16,17 and
reported during the clinical trials.5,12 a decreased rate of severe infection16, but
there is still a possibility of a small percentage
Our data show that only 74(25%) out of of mild to moderate infection after the vaccine.
295(164 after 1st dose and before 2nd dose plus
131 after two vaccine doses) were hospitalized, In our study, both with or without prior
for isolation or treatment. The hospital data infection before vaccines, the reinfection
show none required ventilator support and and/or breakthrough infections were mild to
mortality was nil. The hospital policy has been moderate without severe or critical cases,
revised to admit only those who require none required ICU care or ventilator support.
oxygen support and further treatment We found breakthrough infections (≥14 d) in
otherwise home isolation for 2w. Most of the 83(10.1% of 819), and early breakthrough, i.e.,
studies report breakthrough infections are <14d in 48 (5.9% of 819) after a complete
mild. The Indian Council of Medical Research vaccine of two doses. Infection after the
(ICMR) reports 9.8% of infections required incomplete vaccine, i.e., after 1st and before 2nd
hospitalization, and fatality of 0.4%.13 Another dose was higher occurring in 164 (18.9%).
Indian study reports only 5.5%(6 of 108) Thus, until full immunity is developed after
breakthrough infections required vaccination, common measures of non-
hospitalization for mild to moderate symptoms, pharmaceutical interventions (NPI) should be
none required oxygen or ICU care and observed. In a similar study of 326 HCWs, 65
mortality was nil.3 Similar studies among HCWs (19.9%) breakthrough infections occurred
from India found breakthrough infections were after at least one dose vaccine and before 2nd
11%(36 infections out of 326 HCWs) and the dose or <14 d of 2nd dose.4 Longitudinal studies
majority (94.4%) were mild, not requiring on mRNA vaccines ha reported total infections
oxygen therapy.4 Literature and our findings on after the vaccine occurred in 189(0.8% of
breakthrough infections following vaccines are 22,729 HCWs), out of which only 26 (13.8% of
reassuring that vaccine rollout is effective in 189) occurred in ≥14 d of 2nd dose. This
the control and prevention of COVID-19. emphasizes the role of NPIs until full immunity
is achieved after the vaccine.18

14 Journal of Patan Academy of Health Sciences. 2021Aug;8(2):10-17.

 Jay Shah: Breakthrough infection after COVID-19 vaccine

In our survey, breakthrough infections among vaccination (among 18 UP residents who

females were more common (71.1% out of 83) inadvertently received mixed doses of
than males, but statistically not significant. A Covishield and Covaxin) was safe and possibly
study from India reports 72 (66.7% out of 108) effective against VOCs.25 In Nepal there is no
breakthrough infections occurred in females.3 policy of mixing vaccines as of yet.
In a large series by CDC America, 2/3rd (65%) of
infections occurred in women, and among fatal Vaccine coverage of 70% is the minimum to
COVID-19 vaccine breakthrough infection (of control the ongoing pandemic, which also
1,949 out of 123 million) 980 (50%) were requires taking into consideration decreased
female.2 The CDC argued that more immunity over time, transmission by children
breakthrough infections in females could have and adolescents (who are not included in mass
been due to the tendency of women to get vaccination), and inequitable access, delivery,
tested more than men. The CDC America and distribution of vaccine around the world.26
revealed that among 5,800 breakthrough Priority supply to COVAX and not the bilateral
infections among 77 million vaccinated (commercial or political) deal maintain the
persons, 1/3rd (29%) were asymptomatic, 396 equitable vaccines for the global good.27
(6.8%) required hospitalization, and 74 (1.3%) Vaccine coverage is the ultimate measure for
died from COVID-19. All ages were affected, control of ongoing pandemics and thus the
but 40% occurred in >60 y, possibly more countries with vaccine production capacity and
infection due to virus variants of concern (VOC) resources need to consider that ‘no country is
B.1.351 (SA variant).2,19 The VOCs are safe until every country is safe’.10,28
increasingly responsible for more infections
reported recently.10,18,20 The European To maintain a functional environment in the
Medicines Agency (EMA) and the European ongoing COVID-19 pandemic, staged
Centre for Disease Prevention and Control vaccination includes a priority for essential
(ECDC) strongly recommend vaccination21, and workforces like HCWs, law enforcement,
also WHO because vaccination effectively security, nursing homes, social welfare
prevents severe illness and death by VOCs. institutes, community services, energy, food,
and transportation sectors, and overseas
In Nepal, VOCs have been confirmed. Among workers/students; followed by older adults,
the 14 traveler mountaineers, six were individuals with underlying health conditions
symptomatic while three required and pregnant women to reduce the severity,
hospitalizations and a 61-y with two-dose and lastly extension to adults without
mRNA-1273 had a breakthrough infection by underlying health conditions and children to
Delta variant B.1.617.2.22 We did not conduct stop virus transmission.29 Caution for the lifting
genome sequencing due to lack of logistics. of NPIs is necessary as shown by a data-driven
The ICMR found that >86% of the model of COVID-19 from China for the need of
breakthrough infections were due to the Delta NPIs for one year after the start of vaccination
variant, 9.8% required hospitalization with a i.e. throughout 2021, to prevent the outbreaks
fatality of 0.4%.13 The study also reported that and their escalation.30
the Alpha variant was predominant in north
India, while Delta and Kappa in the rest of the In Nepal, VOCs ‘B.1.1.7’, ‘B.1.617.1’ ‘B.1.617.2’
country. have been confirmed.31 Limitations of this
study might be contributed by factors like
The Chinese Centre for Disease Control and missed asymptomatic individuals with
Prevention (CCDC) in early Apr 2021 allowed breakthrough infection due to lack of policy to
mixing vaccines to boost immunity.23 Gao Fu, test all vaccine recipients, and the causative
the head of the CCDC revealed that he got the VOCs genome sequencing for possible VOCs
3rd dose of different COVID-19 vaccines and due to lack of resources. However, the hospital
that a booster dose may protect against new data show that there was no severe
variants.24 The ICMR found that a mixed breakthrough infection requiring ventilator

15 Journal of Patan Academy of Health Sciences. 2021Aug;8(2):10-17.

 Jay Shah: Breakthrough infection after COVID-19 vaccine

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