The prevalence of AstraZeneca COVID-19 vaccine side effects among Nigist Eleni Mohammed memorial comprehensive specialized hospital health workers. Cross sectional survey.

INTRODUCTION: The best way to eradicate corona virus disease (COVID-19) viral infection is mass vaccination. Many studies demonstrate vaccination is associated with some local and systemic side effects. This study aimed to provide evidence on AstraZeneca COVID-19 vaccine side effects.
METHODOLOGY: Institutional based cross-sectional survey was conducted among 254 health workers at Nigist Eleni Mohammed memorial comprehensive specialized hospital (from July 01/ 2021 to July 30/2021). Data were collected consecutively through self-administered online survey created on Google Forms of platform which had been randomly delivered via (Facebook or telegram pages). Demographic data of participants, side effect after first and second dose of vaccine were covered. RESULT: The prevalence of at least one side effect after first dose was 91.3% and after second dose was 67%. Injection site pain (63.8% vs. 50.4%), headache (48.8% vs. 33.5%), fever (38.8% vs. 20.9%), muscle pain (38.8% vs. 21.7%), fatigue (26% vs. 28.7%, tenderness at the site (27.6% vs. 21.7%), and joint pain (27.6% vs. 20.9%) were the most commonly reported side effects after first and second dose vaccine respectively. Most of participants reported that their symptoms emerged after 6hr of vaccination and only less than 5% of participant's symptoms lasted more than 72hr of post vaccination. The younger age (≤29 year) were more susceptible to at least one side effect (χ 2 = 4.2; p = 0.04) after first dose.
CONCLUSION: The prevalence of side effect after first and second dose vaccine was higher. Most of the symptoms were short lived and mild. This result might help to solve an emerging public health challenge (vaccine hesitancy) nurtured by misinformation related to vaccines safety.

Introduction

Corona viruses are single stranded ribonucleic acid (RNA) viruses that cause upper respiratory tract infection [1]. A clinical specimen from a patient having severe acute respiratory syndrome identified a novel coronal virus and named severe acute respiratory syndrome (SARS-CoV-2) [2].

The principal way for transmission of SARS-COVID 19 virus the exposure of the host to respiratory fluid containing the virus primarily Inhalation of air carrying virus, Deposition of virus onto exposed mucous membranes and touching surface exposed to respiratory fluid containing the virus [3].

Pathogenesis of COVID-19 begins when glycoprotein spike on the surface of the virus binds with angiotensin converting enzyme (ACE) receptor of host cell [4]. After binding the viral particle get access to host cell through endocytosis [5]. The fused viral genome carries out a series enzymatic process transported by Golgi vesicles to the cell membrane and released into the extracellular space through exocytosis [6].

Multiple genomic sequence of the virus has made the development of effective vaccine to be limited [7]. 259 vaccine trials are proceeding from November 11, 2020 and the lack of effective vaccine has cost many lives. Several vaccines are developed from numerous trials, from those vaccine one of the vaccine made by AstraZeneca COVID-19 vaccine [8]. COVID-19 Vaccine AstraZeneca is indicated for active immunisation to prevent COVID-19 caused by SARS-CoV-2, in individual’s ≥18 years old. The Vaccine AstraZeneca is a monovalent vaccine composed of a single recombinant, replication-deficient chimpanzee adenovirus (ChAdOx1) vector encoding the S glycoprotein of SARS-CoV-2. Following administration, the S glycoprotein of SARS-CoV-2 is expressed locally stimulating neutralising antibody and cellular immune responses [9].

The Ethiopian Federal ministry of health has confirmed a coronavirus disease (COVID-19) case on March 13, 2020 in Addis Ababa. The case was announced first to be reported in Ethiopia since the beginning of outbreak in China in December 2019.

COVID-19 Vaccine AstraZeneca has been assessed based on an short-term analysis of pooled data from four on-going randomised, blinded, controlled trials: a Phase I/II Study, COV001, in healthy adults 18 to 55 years of age in the United kingdom (UK); a Phase II/III Study, COV002, in adults ≥18 years of age (including the elderly) in the UK; a Phase III Study, COV003, in adults ≥18 years of age (including the elderly) in Brazil; and a Phase I/II study, COV005, in adults aged 18 to 65 years of age in South Africa [9].

The vaccination course consists of two separate doses of 0.5 ml each. The second dose should be administered between 4 and 12 weeks after the first dose. Individuals who have taken the first dose of COVID-19 Vaccine AstraZeneca should receive the second dose of the same vaccine to complete the vaccination course. The most frequently reported adverse reactions were injection site tenderness injection site pain, headache, fatigue, myalgia, malaise [10].

Vaccine hesitancy (VH) refers to the “delay in acceptance or refusal of vaccines despite availability of vaccine services”; it is an emerging public health challenge nourished by misinformation related to vaccines effectiveness and safety [11]. This finding was supported in the context of COVID-19 vaccines, because a fear of side effects was the most prominent reason to decrease the readiness of healthcare workers and students in Poland to accept the vaccination [12].

Published data to support adverse reaction of AstraZeneca COVID-19 vaccine are lacking which is a driver of vaccine hesitancy. The knowledge about what happens post vaccination in the actual world among the general population is still modest, thus, by describing what to expect after 1st and 2nd dose of vaccination will help in lowering the apprehension about this type vaccines, increased the public confidence in the vaccines, safety, and accelerates the vaccination process against COVID-19.

The results of this study will be reassuring to those who are fearful of the AstraZeneca COVID-19 vaccine. So, the goal of this study to provide evidence on AstraZeneca COVID-19 vaccine side effects after receiving 1st and 2nd dose of it.

Materials and methods

An institutional based cross sectional survey was conducted from July 01, 2021 to July 30, 2021 at Nigist Eleni Mohammed memorial comprehensive specialized hospital (NEMMCSH) which is found 230km from capital city of Ethiopia, in Hossana town, Hadiya zone, Ethiopia.

The required data were collected after obtaining ethical clearance from Wachemo University College of medicine and health science institutional review committee. Written informed consent form that included statements about voluntary participation and anonymity was sought from all the respondents prior to data collection. This was accomplished by sending a standardized general invitation letter with the survey link to accept or decline participation to those who took both dose of AstraZeneca COVID-19 vaccine.

The participant who declined consent was not permitted to open the survey and participate in the study, and participants could withdraw from the survey at any time. The members who clicked on the link were directed to the Google forms and to avoid the missing data, the participants will be requested to fill all the questions of the survey or else could not proceed to the next section. No incentives or compensations have been given to participants.

The study employs a self-administered online survey created on Google Forms of platform which had been randomly delivered to NEMMCSH health workers via (Facebook or telegram pages). Potential participants are directed to a page that included brief introduction to the aim and purpose of the study. Data were collected from all who took both dose of the vaccine and sent response during data collection period.

The survey will include two sections, the first section included demographic questions such as (gender, age, profession) second section reviewed the presence of participant’s chronic conditions and AstraZeneca COVID-19 vaccine side effects (pain at the vaccination site, tenderness, redness, fever, headache, fatigue, nausea, diarrhoea, muscle pain, back pain). For pilot testing, a questionnaire was passed randomly to 15 participants recently vaccinated and filled the questionnaire after taking the two doses and have been excluded from the study.

The Statistical Package for the Social Sciences (SPSS) version 20.0 was used to carry out descriptive statistics for the demographic variable’s similarly, chi square test analysis were performed to assess the correlation between the presence of vaccine side effects and demographic variables. The results were presented by using text, tables, charts and graph.

Results

Demographic characteristics of participants

A total of 261 responses were received from respondents. From the total number of responses 7 participants data was incomplete and totally 254 participants were included in the final analysis. 98(38.6%) were females, 156(61.4%) were males and the mean age of the respondents was 29.9±5.8 years old with the median age of 28.5. About 13(5.1%), 68(26.8%), 124(48.8%), 37(14.6%) and 12(4.7%) were Anaesthetists, Medical doctors, Nurse/Midwife, Pharmacy professional/Lab technicians and Public health experts, respectively. From the total participated health workers, 149(59%) have ≤5 year of work experience and the rest of participants work experience was >5 years (Table 1). Among 254 health workers majority 210 (82.7%) were not tested and 44 (17.3%) tested for COVID-19. Out of 44 health works tested, 19 (43.18%) of them reported positive.

Table 1

Demographic characteristic of participants who took AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

Variables	Category	Frequency (%)
Sex	Female	98(38.6%)
	Male	156(61.4%)
Age	≤29 year old	145(57%)
	>29 year old	109(43%)
Year of experience	≤5 year	149(59%)
	>5 year	105(41%)
Profession	Anaesthetist	13(5.1%)
	Medical doctors	68(26.8%)
	Nurse/ Midwife	124(48.8%),
	Pharmacy professionals/Medical Lab technologist	37(14.6%)
	Public health officer	12(4.7%)

Prevalence of side effects after first dose vaccine

From the total number of respondents (254), 91.3% (232) participants have reported at least one side effect after first dose of vaccine. Over all, injection site pain was the most prevalent side effect followed by headache (48.8%), fever (38.8%) and muscle pain (38.8%). The prevalence of at least one side effect is slightly greater on males (93.5% vs. 87.7%). At least one side effect among the younger age group (≤29 year old) is nearly greater than participants whose age was >29 year old (94.4%vs 87.7%, respectively) (Table 2).

Table 2

The prevalence of side effects among health workers after first dose of AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

Side effects	Category
	Yes	No
Injection site pain	162(63.8%)	92(36.2%)
Tenderness at the site	70(27.6%)	184(72.4%)
Fever	98(38.6%)	156(61.4%)
Muscle pain	98(38.6%)	156(61.4%)
Fatigue	66(26%)	188(74%)
Back pain	52(20.5%)	202(79.5%)
Joint pain	70(27.6%)	184(72.4%)
Diarrhoea	14(5.5%)	240(94.5%)
Headache	124(48.8%)	130(51.2%)
Nausea	12(4.7%)	242(95.3%)

Onset and duration of side effects after first dose of vaccine

From the total number of respondents who experienced Side effect, 52.5% of them felt the side effect after 6hr of vaccination and followed by 26.7% (after 1 to 2hr), 18% (3 to 5hr), and 3% (immediately) (Fig 1).

Fig 1

The duration of side effects of among health workers after first dose of AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

Prevalence of side effects after second dose vaccine

A total of 69.7% of participants reported to have at least one side effect after second dose of AstraZeneca COVID-19 vaccine. From the rest of side effects, again injection site pain was the most reported symptom with the magnitude of 50.4% and followed by headache 33.5%, fatigue 28.7%, and tenderness at the site 21.7%, fever 20.9% and joint pain 20.9%. There was no difference on the prevalence of at least one side effect between participants whose age is ≤29 year old and >29 year old (69.7% vs. 69.7%). Regarding sex, there was also no much difference on prevalence of at least one side effect between the two group’s male and female (68.5% vs. 71%, respectively) (Table 3).

Table 3

The prevalence of side effects among health workers after second dose of AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

Side effects	Category
	Yes	No
Injection site pain	128(50.4%)	126(40.6%)
Tenderness at the site	55(21.7%)	199(78.3%)
Fever	53(20.9%)	201(79.1%)
Muscle pain	55(21.7%)	199(78.3%)
Fatigue	73(28.7%)	181(71.3%)
Back pain	52(20.5%)	202(79.5%)
Joint pain	53(20.9%)	201(79.1%)
Diarrhoea	14(5.5%)	240(94.5%)
Headache	85(33.5%)	169(66.5%)
Nausea	22(8.7%)	232(91.3%)

Onset and duration of side effects after second dose of vaccine

From the total participants who has experienced at least one side effect, most of emerged after 6hr (39%) of vaccination and followed by 35% (within 1 to 2hr), 14.7% (within 3 to 5hr) and 11.3% of them immediately. 54.3% of participants who experience at least one side effect didn’t take any treatment measure for the symptoms and about 16.1% of respondents just took bed rest. 29.5% of participants took anti pain to relieve the symptoms (Fig 2).

Fig 2

The duration of side effects of among health workers after second dose of AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

Correlation between side effects and participant’s age

After first dose of vaccine, the study finding reveals there is significant difference (p = 0.04) between those who were under the age of 29 years and suffering from COVID-19 vaccine side effects and those over the age of 29. There was no significant difference between the two groups (Age ≤29 vs. >29) on side effect reported after second dose of vaccine (Table 4).

Table 4

The correlation of participant’s age and side effect after first and second dose of AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

	Frequency (%)		Chi-square
	Age ≤29(year) (n = 145)	Age >29(year) (n = 109)	P value
Side effect after 1st dose	137(94.4%)	95(87.7%)	0.04
Side effect after 2nd dose	101(69.7%)	76(69.7%)	0.999

Chi-squared test were used with a significance level of <0.05.

Correlation between side effects and participant’s sex

The study result demonstrates there were no significant differences in the number of female participants who reported side effects compared to males after both first and second dose of vaccine (Table 5).

Table 5

The correlation of participant’s sex and side effect after first and second dose of AstraZeneca COVID-19 vaccine from July 01, 2021 to July 30, 2021 in Nigist Eleni Mohammed memorial comprehensive specialized hospital.

	Frequency (%)		Chi-square
	Male (n = 156)	Female (n = 98)	P value
Side effect after 1st dose	146(93.5%)	86(87.7%)	0.108
Side effect after 2nd dose	107(68.5%)	70(71%)	0.63

Chi-squared test were used with a significance level of <0.05.

Discussion

Most of the studies assessed the adverse reaction of Pfizer, Moderna and BioNTech vaccines. There were no sufficient published studies done on side effect of AstraZeneca COVID-19 vaccine. The first shipment of the AstraZeneca vaccines produced by Serum Institute of India (SII) arrived in Ethiopia on 6 March 2021. AstraZeneca was used in our study area among health professionals. Last updated December 2021, three vaccines approved for use in Ethiopia; Oxford/AstraZeneca, serum institute of India/ Covidshield and Sinopharm/ Vero cells. AstraZeneca is the widely used in many setups and the first being available in Ethiopia.

Over all the finding of this study demonstrates the side effects of this vaccine appear to be mild. According to this study more than 90% of respondents have experienced side effect during the first shot. The prevalence of side effect during the second shot of vaccine was lower than the first dose (69.7%), none of this symptoms are serious in nature and requires hospitalization. This result is in line with the cross-sectional survey-based study among German healthcare workers, the frequency of experiencing at least one side effect were 88.1% [13]. Another study conducted in India, 65.9% of respondents reported at least one post-vaccination symptom [14]. A cross sectional survey conducted on residents of Poland shows, among those vaccinated with the first dose of the AstraZeneca vaccine, 96.5% reported at least one post-vaccination reaction. 17.1% of respondents reported all the side effects listed in the survey [15]. The variation in prevalence might be related with unequal sample size or difference in demographic distribution.

According to our study finding, injection site pain was the most prevalent side effect during both first and second dose of vaccine (63.8% vs. 50.4%) and followed by headache (48.8% vs 33.5%), fever (38.8% vs. 20.9%), muscle pain (38.8% vs 21.7%), fatigue (26% vs. 28.7%, tenderness at the site (27.6% vs. 21.7%), and joint pain (27.6% vs. 20.9%). Injection of drug at contracted muscle leads to pain at the site. Injection site pain was reported by many studies to be the most frequent side effect of post vaccination. Cross sectional survey conducted in Czech Republic health workers demonstrates 89.8% of participants reported to have injection site pain and followed by fatigue (62.2%), headache (45.6%), muscle pain (37.1%), and chills (33.9%) [16]. Another study conducted on Saud Arabian inhabitant also reported the short term side effect after first and second dose of COVID-19vaccine. According to this study the most common symptoms were injection site pain, headaches, flu-like symptoms, fever, and tiredness [17].

According to our study, most of respondent’s side effects emerged after 6hr of vaccination during both first and second dose of COVID-19 vaccine (52.5% vs. 39%, respectively). Nearly quarter of respondents after first dose and 35% of respondents after second dose reported the onset of symptom was after 1 to 2hr of post vaccination. Regarding the duration of symptoms, most of participants responded their symptoms disappeared with in the first 24 to 48hr of vaccination on both first and second dose of vaccine (44%vs34%, respectively). Only 3% of respondent’s symptoms after first dose and 5% of respondent’s symptoms after second dose have lasted more than 72hr of post vaccination. This finding is in line with many of studies undergone to assess the side effect of COVID-19vaccine [13–15, 17].

In our study the younger age (≤29 year) were more susceptible to at least one side effect (χ 2 = 4.2; p = 0.04) after first dose of AstraZeneca COVID-19 vaccine. This result is in line with a study done to assess the side effect of COVID-19 vaccine among German health workers [13] and another Cross sectional survey undergone among individuals in UAE [18]. However difference in terms of side effect between male and female were not statistically significant after both first and second dose vaccine.

Strength and limitation of the study

The finding of this study should be interpreted cautiously regarding the external validity since sex and profession of participants are not equally distributed. The data was collected online through Google form so that only respondents who are motivated will fill and submit the questions which might result for selection bias. Data were collected from health workers who have good understanding about the nature of items, so the outcome were expected to be reported correctly. The data were self-reported which strengthen its objectivity. To the best of our knowledge, this is the first study conducted to assess the side effect of AstraZeneca COVID-19 vaccine among health workers resource limited setting.

Conclusion

The prevalence of side effect after first and second dose vaccine was higher. Most of the symptoms were short lived, mild and doesn’t require hospitalization. This result might help to solve an emerging public health challenge (vaccine hesitancy) nurtured by misinformation related to vaccines safety.

(XLSX)

Click here for additional data file.

3 Dec 2021

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Sanjay Kumar Singh Patel, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

1. When submitting your revision, we need you to address these additional requirements.

Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Thank you for stating the following financial disclosure:

(No.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.)

At this time, please address the following queries:

a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution.

b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

c) If any authors received a salary from any of your funders, please state which authors and which funders.

d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

3. PLOS requires an ORCID iD for the corresponding author in Editorial Manager on papers submitted after December 6th, 2016. Please ensure that you have an ORCID iD and that it is validated in Editorial Manager. To do this, go to ‘Update my Information’ (in the upper left-hand corner of the main menu), and click on the Fetch/Validate link next to the ORCID field. This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager. Please see the following video for instructions on linking an ORCID iD to your Editorial Manager account: https://www.youtube.com/watch?v=_xcclfuvtxQ

4. Please amend the manuscript submission data (via Edit Submission) to include author Ajay Prakesh.

5. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

6. We suggest you thoroughly copyedit your manuscript for language usage, spelling, and grammar. If you do not know anyone who can help you do this, you may wish to consider employing a professional scientific editing service.

Whilst you may use any professional scientific editing service of your choice, PLOS has partnered with both American Journal Experts (AJE) and Editage to provide discounted services to PLOS authors. Both organizations have experience helping authors meet PLOS guidelines and can provide language editing, translation, manuscript formatting, and figure formatting to ensure your manuscript meets our submission guidelines. To take advantage of our partnership with AJE, visit the AJE website (http://learn.aje.com/plos/) for a 15% discount off AJE services. To take advantage of our partnership with Editage, visit the Editage website (www.editage.com) and enter referral code PLOSEDIT for a 15% discount off Editage services.  If the PLOS editorial team finds any language issues in text that either AJE or Editage has edited, the service provider will re-edit the text for free.

Upon resubmission, please provide the following:

The name of the colleague or the details of the professional service that edited your manuscript

A copy of your manuscript showing your changes by either highlighting them or using track changes (uploaded as a *supporting information* file)

A clean copy of the edited manuscript (uploaded as the new *manuscript* file)

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript by Desalegn et al. “The prevalence of Astrazeneca covid 19 vaccine side effects among Nigist Eleni Mohammed memorial comprehensive specialized hospital health workers. Cross sectional survey” is an interesting study about prevalence of Astrazeneca covid 19 vaccine side effects. Authors have conducted a survey on 254 health workers via self-administered online survey created on Google Forms and collected demographic data of participants, side effect after first and second dose of vaccine. Authors have concluded that the prevalence of side effect after first and second dose vaccine was higher. This study is noteworthy and the manuscript requires minor revision before its publication.

Comments

1. Did authors inquire about the COVID-19 infection status of their participants? This will be interesting to know and authors can include this data to their study.

2. At least one additional Figure (illustration) may be provided as to highlight the summary or prospect of this study.

3. The English of manuscript can be polished (minor).

4. The abbreviations should be cross validated in the manuscript (First define them fully followed by abbreviation) and one paragraph can be added for abbreviations.

5. Authors should discuss about the symptoms they found in their study and the reason of these symptoms in discussions.

Reviewer #2: In this paper entitled "The Prevalence of Astrazeneca COVID 19 Vaccine side effects among Nigist Eleni Mohammed memorial comprehensive specialized hospital health worker. cross-sectional survey", the

authors investigate AstraZeneca covid 19 vaccine side effects among health workers. They have done a cross-sectional survey among 254 health workers from July 01, 2021, to July 30, 2021, using google form. The study reported injection site pain, headache, fever, muscle pain, fatigue, and joint pain after the first and second vaccines. However, the symptoms are short-lived and mild. The study is easy to understand and concise. Nevertheless, it requires some minor comments to be answered for publication.

Minor comments:

1) The English may be polished for publication.

2) Please add few lines about the COVID-19 situation in Ethiopia and what COVID-19 vaccines are available other than Astrazeneca in Ethiopia, and if other vaccines are available. Why did the author include only Astrazenca covid-19 in the study?. Is a comparative analysis between the symptoms of different vaccines possible ?.

4) There are many formatting errors in the manuscript and referencing is also not consistent. Please correct it.

5) The author may provide a paragraph regarding challenges or prospects of study in the discussion.

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.