Evaluation the Effectiveness of AstraZeneca's COVID-19 Vaccine

After 6 Months of the Second Dose

Windi Marti Ningsih

, Liandhajani and Diana Laila Ramatillah

Faculty Pharmacy, Universitas 17 Agustus 1945 Jakarta, Indonesia

Keywords: COVID-19, Effectiveness, Astrazeneca.

Abstract: Growing efforts are being made to socialize the vaccination program in order to establish a global herd

immunity. In clinical trials of strategy and development, the astrazeneca vaccine's efficacy is a crucial concern.

The purpose of this study was to evaluated the effectiveness of Astrazeneca’s Covid-19 vaccine after 6 months

of the second dose. This study was conducted to evaluate the effectiveness of the Astrazeneca vaccine after 6

months of the second dose in Indonesian people. This type of research is observational with a cross sectional

design. This method is done by direct observation of the survey data. This research requires ethical approval

No.40/KEPK-UTA45JKT/EC/EXP/07/2022. The results of this study showed that there was a significant

relationship between sociodemography and the incidence of COVID-19 infection after administration of the

AstraZeneca vaccine such as gender, age, and BMI. The most common side effect of receiving AstraZeneca

is pain at the injection site. The effectiveness of the astrazeneca vaccine can be seen from the average not

exposed to covid-19, which is 95% where the Covid-19 vaccine in this study is safe for gender and age > 18

years.

1 INTRODUCTION

The respiratory condition known as Coronavirus

2019 (covid-19) is brought on by the pandemic-

causing severe acute respiratory syndrome

coronavirus 2 (sars-cov-2) (Vesselaldo & Ramatillah,

2022). Chinese health officials alerted the WHO

towards the end of 2019 about unidentified

pneumonic cases in Wuhan, Hubei Province, China.

At early January, throat swab sample from a patient

led to the discovery of a novel coronavirus (ncov-

2019). The pathogen is then given the names

coronavirus disease 2019 (Covid-19) by WHO and

severe acute respiratory syndrome coronavirus 2

(SARS-CoV-2) by coronavirus study group.

(Harapan et al., 2020).

The incubation period for COVID-19 is between

1-14 days, ranging from 3 to 7 days. The most

common symptoms in mild to moderate patients are

fever, fatique, and a dry cough accompanied by other

symptoms such as headache, nasal congestion, sore

throat, muscle aches, and joint pain (Yang et al.,

https://orcid.org/0000-0001-8144-9907

https://orcid.org/0000-0002-3921-3455

2020). Until January 2022 SARS-CoV 2, virus that

started the COVID-19 pandemic, had already killed

more than 5.5 million people. One of the current

vaccine which is one of the most popular treatments

available for the Covid-19 pandemic is an adenoviral

vector based vaccine (Barin et al., 2022).

The astrazeneca vaccine was created by the

University of Oxford and clinical trials were

conducted in the UK, Brazil and South Africa

(Voysey et al., 2021). A vaccine called Astrazeneca

was created using a genetically altered virus (viral

vector). This type of vaccine functions by

encouraging or inducing the body to develop

antibodies that fight infection with the SARS-CoV-2

virus (Pane, 2021). The decline of serum SARS-CoV-

2 antibodies has been brought up questionable long-

term immunity, which have been linked to

breakthrough infections and led to the consideration

of extra booster doses of the vaccine (Padoan et al.,

2022).

Study conducted by scientists at King's College

London showed that protection from a full-dose

Astrazeneca Covid-19 vaccine dropped within 6

Ningsih, W., Liandhajani, . and Ramatillah, D.

Evaluation the Effectiveness of AstraZeneca’s COVID-19 Vaccine After 6 Months of the Second Dose.

DOI: 10.5220/0011978300003582

In Proceedings of the 3rd International Seminar and Call for Paper (ISCP) UTA â

Z45 Jakarta (ISCP UTA’45 Jakarta 2022), pages 179-185

ISBN: 978-989-758-654-5; ISSN: 2828-853X

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

179

months. Protection 1 month after the second dose of

Astrazeneca vaccine drops from 77% to 67% after 4

to 5 months (Sorongan, 2021).

According to research by The BMJ Covid-19

booster vaccines: What we know and who's doing

what that immunity is indeed reduced, especially

against the delta variant (Mahase, 2021). Researchers

found that a single dose of the Oxford-Astrazeneca

vaccine was only about 30% effective against delta,

although two doses were more effective: 67% for

Astrazeneca (Mahase, 2021b). In an experimental

study, antibody responses to a single dose of

Astrazeneca (AZ) (ChAdOx1 nCoV-19) vaccine

(Astrazeneca, Lund, Sweden) using five SARS-CoV-

2 antibody tests showed that seroconversion rates

after the first vaccination ranged from 66.2% up to

92.5%, which is consistent with previous studies

(Jeong et al., 2021).

Although data relating to the effectiveness of the

astrazeneca vaccine already exist. Further clinical

research is needed on the Evaluation of the

Effectiveness of the Astrazeneca Covid-19 Vaccine

after 6 months of the second dose, by looking at

various other aspects such as sociodemography that

allows for an association with the efficacy and side

effects of the astrazeneca vaccine.

2 METHOD

2.1 Design

This study used mixed methods and a prospective

cross-sectional study by collecting primary data from

Indonesian people who had received the complete

dose of Astrazeneca vaccine. This research was

conducted over a period of 4 months (April-July). For

inclusion criteria, all Indonesian people aged >18

years who have received the second dose of

AstraZeneca vaccine for more than 6 months and are

willing to be respondents in this study. The exclusion

criteria for all Indonesian people with cancer,

HIV/AIDS patients, TB patients, autoimmune

patients (lupus patients) and less than 6 months of the

second dose will be excluded in this study.

2.2 Participant

Participants in this study were Indonesian people >18

years old who had received the complete dose of

AstraZeneca vaccine with a total of 310 respondents.

2.3 Instrument

This study used questionnaires distributed through

social media (WhatsApp, Facebook, Instagram,

Telegram and Twitter). The total number of

questionnaires in this study were 62 of identity

questions and comorbidities. 62 of these questions

were about side effects received after the first and

second doses of vaccination short-term and long-term

and monitoring of side effects from the vaccine for 1-

6 months after being vaccinated.

2.4 Statistic Analysis

The collected results were analyzed using SPSS

version 25 application. Fisher, Chi-Square, Mann-

Whitney, and Kruskal Wallis tests were used to find

associations between risk factors (gender, age, BMI)

and side effects. A p-value of 0.05 was considered

significant.

2.5

Ethical Approval

This study was reviewed and approved by the

University Ethics Committee 17 August 1945 on 26

July 2022 (No.40/KEPK-

UTA45JKT/EC/EXP/07/2022).

3 RESULT

3.1 Demographic Characteristic

This study was conducted based on demographic

status, namely gender as many as 310 respondents in

this study consisted of 73 men (23.5%), and 237

women (76.5%) with an age range of 18-25 years 225

(72.5 %), 26-40 years 76 (24.3%), 41-50 years 5

(1.5%) and 51-57 years 4 (1.2%). Respondents are

also spread across several parts of Indonesia, around

10.0% from Sumatra, 85.2% from Java, 3.9% from

Kalimantan, 0.3% from Papua, and 0.6% from

Sulawesi. Based on comorbid diseases, most of the

respondents in this study 289 people (93.2%) did not

have comorbid diseases, 5 people (1.6%) with

comorbid diabetes, 2 people (0.6%) hypertension and

the last 14 people ( 4.5%) Asthma. (Table 1).

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180

Table 1. Demographic characteristic (N=310).

Variables Fre

uenc

Percenta

e (%)

Gende

Male 73 23,5%

Female 237 76,5%

Age

18-25 225 72,5%

26-40 76 24,3%

41-50 5 1,5%

51-57 4 1,2%

Domicile

Sumatera 31 10,0%

Jawa 264 85,2%

Kalimantan 12 3,9%

Papua 1 0,3%

Sulawesi 2 0,6%

Comorbi

Diabetes 5 1,6%

ertension 2 0,6%

Asthma 14 4,5%

3.2 Side Effect after Vaccination

Table 2: Side Effect after Vaccination.

Variables

Frequency /

Persentage

(%)

1st dose

(n=310)

Frequency /

Persentage

(%)

2nd dose

(n=310)

Side effect 1st dose

vaccination

Fever 182 (58,7%) 109 (35,2%)

Pain in the injection

area 233 (75,2%) 188 (60,6%)

Cough 39 (12,6%) 28 (9%)

Flu 60 (19,4%) 37 (11,9%)

Nausea 56 (18,1%) 28 (9%)

Dia

rhea 17 (5,5%) 18 (5,8%)

Dizziness 140 (45,2%) 96 (31%)

Sleepiness 156 (50,3%) 130 (41,9%)

Dehyd

ate

72 (23,2%) 49 (15,8%)

Bleeding 3 (1%) 2 (0,6%)

Pain in the upper ar

200 (64,5%) 136 (43,9%)

Cardiovascular

events 10 (3,2%) 7 (2,3%)

Based on table 2, it is known that the common side

effects felt by respondents in this study at the first

dose of AstraZeneca were fever 58.7%, pain at the

injection site 75.2%, cough 12.6%, flu 19.4%, nausea

18,1%, diarrhea 5.5%, dizziness 45.2%, feeling

sleepy 50.3%, thirst or dehydration 23.2%, bleeding

1.0%, upper arm pain 64.5%, and cardiovascular 3.2

%. In the second dose, the side effects were fever

35.2%, pain at the injection site 60.6%, cough 9.0%,

flu 11.9%, nausea 9.0%, diarrhea 5.8%, dizziness

31%, feeling sick. drowsiness 41.9%, thirst or

dehydration 15.8%, bleeding 0.6%, upper arm pain

43.9%, and cardiovascular 2.3%.

3.3 Between Gender and Side Effects

Table 3: Correlation between gender and side effects

Variables

Frequency / Percentage

(%)

value

Male

(n=73)

Female

(n=237)

Side effects 1st

vaccination

Sleepiness

(39,7%) 127 (53,5%) 0,045*

Monitoring 1-3

months after

vaccination

Menstrual

problems 0 23 (9,7%) 0,000#

Monitoring 4-6

months after

vaccination

Menstrual

problems 0 16 (6,7%) 0,000#

*Fisher test,

#Chi-square test

In this study, the variable that had a significant

correlation with the side effects that appeared was

gender. From a total of 310 respondents, 23.5% of

respondents were male and 76.5% were female. The

details of the data are presented in table 3. For

questions about side effects of fisher’s test results and

chi-square test results for follow-up 1-3 months and

4-6 months after vaccination.

Evaluation the Effectiveness of AstraZeneca’s COVID-19 Vaccine After 6 Months of the Second Dose

181

3.4 Between Age and Side Effects

Another variable that has a significant relationship is

age and vaccine side effects. In this study, the overall

age of the respondents was 18-57 years. Most of the

side effects are felt by those who are at the age of 23

years. Detailed data are presented in table 4. from the

results of the Mann-Whitney test for questions about

side effects after receiving the vaccine and the results

of the Kruskal Wallis test for questions about

monitoring side effects after 1-3 months and 4-6

months after vaccination. In accordance with research

that has been done, many side effects are felt by those

who are at the age (median: 23 years).

3.5 Between BMI and Side Effects

The last variable that correlates is BMI. In this study,

individuals who experienced side effects of fever (p =

0.035) and loss of smell (p = 0.013) with an average

BMI (Body Mass Index) of 21.

Table 4: Correlation between age and side effects.

Variables Frequency p-value

Age (n:310 median: 23)

Side effects 1st vaccination

Nauseous 56 (18,1%) 0,040*

Covid-19 infection after 1st dose

Cough and Sore Throat 63 (20,3%) 0,001*

Headache 104 (33,5%) 0,029*

Covid-19 infection after 2nd dose

Cough and Sore Throat 44 (14,1%) 0,011*

Monitoring 1-3 months after vaccination

Infected with Covid-19 11 (3,5%) 0,039#

Menstrual problems 24 (7,7%) 0,001#

Heart problems 6 (1,9%) 0,011#

Monitoring 4-6 months after vaccination

Menstrual problems 16 (5,1%) 0,001#

*Mann-whitney test, #Kruskal wallis test

Table 5: Correlation between BMI and side effects.

Variables

Frequency / Persentage (%)

p-value

BMI (n:310 median 21)

Side effects 1st vaccination

Fever 21 (6,7%) 0,035*

Side effects 2nd vaccination

Loss of smell 13 (4,1%) 0,013*

*Mann-whitney test

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Figure 1: Symptoms of Exposure to Covid-19 1st Dose.

Figure 2: Symptoms of Exposure to Covid-19 2nd Dose.

3.6 The Wffectiveness of the

AstraZeneca Vaccine Based on the

Symptoms of Exposure to Covid-19

Based on Fig 1 and 2. above, it can be seen that most

of the respondents in this study were not exposed to

COVID-19 after the first dose of AstraZeneca

vaccination as much as 97%, asymptomatic 1%, mild

symptoms 1.9%, moderate symptoms 0.3%, and 0%

respondents with severe symptoms. 93% were not

exposed to covid-19 after the second dose of

AstraZeneca vaccination, 1.3% asymptomatic, 5.2%

mild symptoms, 1% moderate symptoms, and 0% of

respondents with severe symptom.

4 DISCUSSION

4.1 Vaccine Side Effects

This study involved 310 people who were fully

vaccinated, participants received a questionnaire that

they experienced the side effects of the vaccine. As

shown in Table 2 of this study found a slight

difference with the study in Vietnam, it was found

that the most common side effects were fever

(69.4%), muscle aches (68.6%), fatigue/drowsiness

(62, 5%), body aches (59.4%), headache (58.3%) and

chills (45.7%) (Tran et al., 2020). Whereas in another

study from Saudi Arabia reported some side effects

such as fatigue (90%), injection site pain (85%), fever

(66%), and headache (62%) (Alhazmi et al., 2021).

The side effect that is most commonly felt is pain in

the injection area, this is in accordance with previous

research conducted in Ethiopia which described that

the most common local effect was pain at the

injection site (65.48%) (Solomon et al., 2021).

4.2 Correlation Between Gender and

Vaccine Side Effects

There was a significant difference between the side

effects felt by the patients and gender. As it was found

that female vaccine recipients had more side effects

than male vaccine recipients. 53.3% of female

respondents experienced side effects of feeling

drowsy after receiving the first dose of vaccine, while

39.7% for males. For monitoring 1-3 months after

vaccination it was found that 9.7% of women who

received the vaccine experienced a change in their

menstrual cycle, while for monitoring 4-6 months

1% (3)

2% (6)

0,3% (1)

0,% (0)

No symptoms Mild Moderate Severe

Symptoms of Covid-19 After Vaccination First Dose

1,3% (4)

5,2% (16)

1% (2)

0% (0)

0,0%

1,0%

2,0%

3,0%

4,0%

5,0%

6,0%

No symptoms Mild Moderate Severe

Symptoms of Covid-19 After Vaccination Second Dose

Evaluation the Effectiveness of AstraZeneca’s COVID-19 Vaccine After 6 Months of the Second Dose

183

after vaccination it was found that 6.7%. See table 3.

Females experience side effects more than males. Out

of 310 respondents reported that women experienced

significant side effects of the first dose such as feeling

drowsy (53.5% ; p-value 0.045) this proves that

women generally have a greater level of antibody

response to viruses, infections and vaccinations

(Scully et al., 2020).

4.3 Correlation Between Age and

Vaccine Side Effects

As the data in table 4 shows, age has an impact on

vaccine side effects. The findings of this study are in

accordance with research that has been done, many

side effects are felt by those who are at the age

(median: 23 years). These results are in agreement

with a study conducted on Bangladeshi population

that reported side effects were much greater in young

adults than in older adults (p = 0.02) (Jahan et al.,

2021). In Hamed Zare's study on health workers in

Iran the frequency of side effects such as injection site

pain, fatigue, headache and fever was higher in those

under 40 years of age (Zare et al., 2021). This

phenomenon is interpreted using the concept of

immunosenescence which refers to the decline in the

function of the immune system with increasing age

(Ramasamy et al., 2020).

4.4 Correlation Between BMI and

Vaccine Side Effects

The last variable that correlates with side effects and

vaccine efficacy is BMI. In this study, individuals

who experienced side effects of fever (p= 0.035) and

loss of smell (p=0.013) with an average BMI (Body

Mass Index) of 21. Vaccine recipients with a BMI

<25 had a higher risk of experiencing side effects

from the vaccine Covid-19 (Sutardi & Ramatillah,

2022).

4.5 The Effectiveness of the

AstraZeneca Vaccine based on the

Symptoms of Exposure to Covid-19

In Figures 1 and 2 of this study, the average 310

respondents who were exposed to COVID-19 after

the first dose of vaccination were 3.3%, and 7.5%

exposed to Covid-19 after the second dose of

vaccination. The results of this study prove that the

effectiveness of the complete dose of AstraZeneca

vaccine can reduce the risk and prevent COVID-19

by up to 94%. A study conducted in the United States

in a phase III trial found that the vaccine produced by

the University of Oxford (AstraZeneca) was 79%

effective in preventing symptoms of COVID-19 and

100% effective in preventing serious illness and

hospitalization (Boytchev, 2021).

5 CONCLUSIONS

The most common side effects is pain in the injection

after the first and second doses. The variables that

affect the side effects and effectiveness of the vaccine

are gender, age and BMI. For gender, female vaccine

recipients experienced significantly more side effects

than males. The age of the vaccine recipients was

dominated by the age of 23 years who experienced

side effects after vaccination. As for BMI, it was

found that vaccine recipients who have BMI < 25 had

a higher risk of experiencing side effects. The

effectiveness of the astrazeneca vaccine can be seen

from the average not exposed to COVID-19, which is

95%. Overall, based on this study the Covid-19

vaccine was safe for gender and age >18 years, in this

study no severe side effects or fatal allergic reactions

were found in AstraZeneca vaccine recipients.

REFERENCES

Alhazmi, A., Alamer, E., Daws, D., Hakami, M., Darraj,

M., Abdelwahab, S., Maghfuri, A., & Algaissi, A.

(2021). Evaluation of side effects associated with

covid‐19 vaccines in Saudi Arabia. Vaccines, 9(6).

https://doi.org/10.3390/vaccines9060674

Barin, B., Kasap, U., Selçuk, F., Volkan, E., & Uluçkan, Ö.

(2022). Comparison of SARS-CoV-2 anti-spike

receptor binding domain IgG antibody responses after

CoronaVac, BNT162b2, ChAdOx1 COVID-19

vaccines, and a single booster dose: a prospective,

longitudinal population-based study. The Lancet

Microbe, 274–283. https://doi.org/10.1016/s2666-

5247(21)00305-0

Boytchev, H. (2021). Covid-19: Germany struggles with

slow uptake of Oxford AstraZeneca vaccine. BMJ

(Clinical Research Ed.), 372(March), n619.

https://doi.org/10.1136/bmj.n619

dr. Merry Dame Cristy Pane. (2021). Vaksin AstraZeneca

atau AZD1222 adalah vaksin untuk mencegah penyakit

COVID-19. Vaksin ini merupakan hasil kerja sama

antara Universitas Oxford dan AstraZeneca yang

dikembangkan sejak Februari 2020. Alodokter.Com.

https://www.alodokter.com/vaksin-astrazeneca

Harapan, H., Itoh, N., Yufika, A., Winardi, W., Keam, S.,

Te, H., Megawati, D., Hayati, Z., Wagner, A. L., &

Mudatsir, M. (2020). Coronavirus disease 2019

(COVID-19): A literature review. Journal of Infection

ISCP UTA’45 Jakarta 2022 - International Seminar and Call for Paper Universitas 17 Agustus 1945 Jakarta

184

and Public Health, 13(5), 667–673.

https://doi.org/10.1016/j.jiph.2020.03.019

Jahan, N., Rahman, F. I., Saha, P., Ether, S. A.,

Roknuzzaman, A. S. M., Sarker, R., Kalam, K. T., Haq,

K., Nyeen, J., Himi, H. Z., Nazmul Hossain, M.,

Chowdhury, M. H., Uddin, M. M., & Alam, N. H.

(2021). Side effects following administration of the first

dose of Oxford-AstraZeneca’s covishield vaccine in

Bangladesh: A cross-sectional study. Infectious

Disease Reports, 13(4), 888–901.

https://doi.org/10.3390/IDR13040080

Jeong, S., Lee, N., Lee, S. K., Cho, E. J., Hyun, J., Park, M.

J., Song, W., Jung, E. J., Woo, H., Seo, Y. Bin, Park, J.

J., & Kim, H. S. (2021). Comparison of the results of

five sars-cov-2 antibody assays before and after the first

and second chadox1 ncov-19 vaccinations among

health care workers: A prospective multicenter study.

Journal of Clinical Microbiology, 59(12).

https://doi.org/10.1128/JCM.01788-21

Mahase, E. (2021a). Covid-19: Two vaccine doses are

crucial for protection against delta, study finds. BMJ

(Clinical Research Ed.), 374(August), n2029.

https://doi.org/10.1136/bmj.n2029

Mahase, E. (2021b). Covid-19 booster vaccines: What we

know and who’s doing what. BMJ (Clinical Research

Ed.), 374(August), n2082.

https://doi.org/10.1136/bmj.n2082

Padoan, A., Cosma, C., Bonfante, F., Della Rocca, F.,

Barbaro, F., Santarossa, C., Dall’olmo, L., Pagliari, M.,

Bortolami, A., Cattelan, A., Cianci, V., Basso, D., &

Plebani, M. (2022). Neutralizing antibody titers six

months after Comirnaty vaccination: Kinetics and

comparison with SARS-CoV-2 immunoassays.

Clinical Chemistry and Laboratory Medicine, 60(3),

456–463. https://doi.org/10.1515/cclm-2021-1247

Ramasamy, M. N., Minassian, A. M., Ewer, K. J., Flaxman,

A. L., Folegatti, P. M., Owens, D. R., Voysey, M., Aley,

P. K., Angus, B., Babbage, G., Belij-Rammerstorfer, S.,

Berry, L., Bibi, S., Bittaye, M., Cathie, K., Chappell,

H., Charlton, S., Cicconi, P., Clutterbuck, E. A., … Zizi,

D. (2020). Safety and immunogenicity of ChAdOx1

nCoV-19 vaccine administered in a prime-boost

regimen in young and old adults (COV002): a single-

blind, randomised, controlled, phase 2/3 trial. The

Lancet, 396(10267), 1979–1993.

https://doi.org/10.1016/S0140-6736(20)32466-1

Scully, E. P., Haverfield, J., Ursin, R. L., Tannenbaum, C.,

& Klein, S. L. (2020). Considering how biological sex

impacts immune responses and COVID-19 outcomes.

Nature Reviews Immunology, 20(7), 442–447.

https://doi.org/10.1038/s41577-020-0348-8

Solomon, Y., Eshete, T., Mekasha, B., & Assefa, W.

(2021). Covid-19 vaccine: Side effects after the first

dose of the oxford astrazeneca vaccine among health

professionals in low-income country: Ethiopia. Journal

of Multidisciplinary Healthcare, 14, 2577–2585.

https://doi.org/10.2147/JMDH.S331140

Sutardi, A. Q. I., & Ramatillah, D. L. (2022). Evaluation

Comparison Between Sinovac and Pfizer Vaccine

Among Indonesian Children and Teenager Under 18

Years Old. International Journal of Applied

Pharmaceutics, 14(Special issue 2), 22–30.

https://doi.org/10.22159/ijap.2022.v14s2.44745

Tommy Sorongan. (2021). Riset Ungkap Perlindungan

Vaksin AstraZeneca Cuma 6 Bulan. CNBC Indonesia.

https://www.cnbcindonesia.com/news/2021082520541

4-4-271294/riset-ungkap-perlindungan-vaksin-

astrazeneca-cuma-6-bulan

Tran, V. N., An, H., Thanh, T., Le, A., Tung, T., & Thao,

P. (2020). Since January 2020 Elsevier has created a

COVID-19 resource centre with free information in

English and Mandarin on the novel coronavirus

COVID- 19 . The COVID-19 resource centre is hosted

on Elsevier Connect , the company ’ s public news and

information . January.

Vesselaldo, M., & Ramatillah, D. L. (2022). Evaluation of

Bmi Relationship With Increased D-Dimer in Covid-19

Patients At a Jakarta Private Hospital. International

Journal of Applied Pharmaceutics, 14(Special Issue 2),

49–53. https://doi.org/10.22159/ijap.2022.v14s2.44749

Voysey, M., Clemens, S. A. C., Madhi, S. A., Weckx, L.

Y., Folegatti, P. M., Aley, P. K., Angus, B., Baillie, V.

L., Barnabas, S. L., Bhorat, Q. E., Bibi, S., Briner, C.,

Cicconi, P., Collins, A. M., Colin-Jones, R., Cutland, C.

L., Darton, T. C., Dheda, K., Duncan, C. J. A., …

Zuidewind, P. (2021). Safety and efficacy of the

ChAdOx1 nCoV-19 vaccine (AZD1222) against

SARS-CoV-2: an interim analysis of four randomised

controlled trials in Brazil, South Africa, and the UK.

The Lancet, 397(10269), 99–111.

https://doi.org/10.1016/S0140-6736(20)32661-1

Yang, C. L., Qiu, X., Zeng, Y. K., Jiang, M., Fan, H. R., &

Zhang, Z. M. (2020). Coronavirus disease 2019: A

clinical review. European Review for Medical and

Pharmacological Sciences, 24(8), 4585–4596.

https://doi.org/10.26355/eurrev_202004_21045

Zare, H., Rezapour, H., Mahmoodzadeh, S., & Fereidouni,

M. (2021). Prevalence of COVID-19 vaccines (Sputnik

V, AZD-1222, and Covaxin) side effects among

healthcare workers in Birjand city, Iran. International

Immunopharmacology, 101(PB), 108351.

https://doi.org/10.1016/j.intimp.2021.108351

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