Factors associated with contracting Covid-19 at a High School in Makonde District, Zimbabwe, November 2020

Kudzai Madamombe¹, Gift Masoja², Tapiwa Dhliwayo², Donewell Bangure³, Tsitsi Juru^1,&, Addmore Chadambuka¹, Emmanuel Govha¹, Notion Gombe¹, Maurice Omondi, Mufuta Tshimanga¹

 

¹Department of Primary Health Sciences. Family Medicine, Global and Public Health Unit, University of Zimbabwe, Harare, Zimbabwe, ²Zimbabwe Ministry of Health and Child Care, Mashonaland West, Zimbabwe, ³Africa Centres for Disease Control and Prevention, Addis Ababa, Ethiopia, African Union, ⁴Africa Field Epidemiology Network, Harare, Zimbabwe, ⁵Africa Field Epidemiology Network, Nairobi, Kenya

 

 

^&Corresponding author
Tsitsi Juru, Department of Primary Health Sciences. Family Medicine, Global and Public Health Unit, University of Zimbabwe, Harare, Zimbabwe. tsitsijuru@gmail.com

 

 

 

 

Corona Virus Disease of 2019 (Covid-19) is a viral respiratory disease first identified in Wuhan, China [1,2]. Countries have employed national lockdowns with quarantine and isolation of infected patients [3] and suspension of social events [4]. The Covid-19 pandemic has increased from an initial 44 patients [5] in China, to over 59 million cases and about 1,300,000 deaths worldwide by 15 November 2020 [6]. Over 900 000 Africans have contracted the virus [6]. Zimbabwe reported 9398 cases and 274 deaths as of 24 November 2020 [7].

 

The Covid-19 outbreak at the School in Makonde District, Mashonaland West Province commenced on the 18^th of November 2020 with the index case testing positive for Covid-19. By the 29^th of November, 73 cases had been confirmed. The outbreak posed a huge burden on the local health care system. The risk factors for contracting Covid-19 in high school students have not been fully characterized. We conducted an outbreak investigation to determine the factors associated with contracting Covid-19 at the School in Makonde District.

 

 

Epidemiological Investigation

 

We collected nasopharyngeal swabs from students for laboratory diagnosis using national guidelines [8]. All Polymerase Chain Reaction (PCR) positive patients were line-listed, an environmental assessment was conducted. We developed the hypothesis that hand hygiene practices were associated with contracting Covid-19.

 

Study Design

 

To minimise investigation time and with the relative rarity of Covid-19 in schools, we chose a case-control design to simultaneously assess risk factors such as handshaking, lack of social distancing, and close contact with an infected person [9]. We conducted an unmatched 1:1 case-control to test the hypothesis.

 

Study Setting

 

The government secondary school was a mixed boarding school with 1391 students in 6 forms. There were six boarding hostels at the school [10] and a staff complement of 44 teachers and 23 support staff. The school health committee had 8 members and there was no school clinic on site.

 

Study Participants

 

The study participants were students of the school present from 18-29 November 2020.

 

Working Definitions

 

A case: Any student who tested Covid-19 PCR positive who lived at the School from 18-29 November 2020.

 

A control: Any student who tested Covid-19 PCR negative who lived at the School from 18-29 November 2020.

 

Study Hypothesis

 

H_o = there was no association between hand hygiene practices and contracting Covid-19

 

H₁= there was an association between hand hygiene practices and contracting Covid-19

 

Sample Size

 

A sample size of 67 cases and 67 controls was calculated using the Fleiss formula in Epi Info 7.2.4.0^™ (CDC, 2020) considering a similar study done by Ssebuufu et al, Awareness, knowledge, attitude and practice towards measures for prevention of the spread of COVID-19 in Uganda [11]. We assumed a 95% confidence level, a power of 80%, a 10% refusal rate and a 50% exposure in cases and 30% exposure in controls and that students not following recommended hand hygiene had an odds ratio of 2.89 of contracting Covid-19.

 

Sampling

 

We selected the cases using simple random sampling by using the RANDBETWEEN Function of Microsoft Excel. Controls were selected using systematic random selection with the line list as a sampling frame where every seventh student was selected. We selected the 8 key informants purposively.

 

Data Collection

 

We pretested the questionnaire at a local nursing school. We conducted interviews to collect data from cases, controls and key informants. The questionnaire collected data on demographic characteristics, signs and symptoms, outcomes, risk factors, and knowledge among others. We used a checklist to assess the school´s preparedness, resource availability and environmental assessment. We checked screening points, classroom size and availability of hand hygiene supplies.

 

Data Analysis

 

We categorised qualitative data according to themes, coded and summarized it, quantitative data was entered into the computer database and means, frequencies, tables, and odds ratios for different variables were run using Epi Info. We generated an epidemic curve of the cases and bivariate and stratified analysis was conducted to check for effect modification and confounding.

 

Availability of data and material

 

The data that support the findings of this study are available from the Ministry of Health and Child Care (Zimbabwe) but restrictions apply to the availability of these data. Data are however available from the authors upon reasonable requests and with permission of the Ministry of Health and Child Care (Zimbabwe).

 

Ethical Considerations

 

We did not collect any of the participants´ personal information. We explained the purpose, procedures involved, potential benefits, possible discomforts, participants´ right to withdraw, and risks. We sought permission to proceed from all relevant authorities and permission from parents/guardians was sought using a written indemnity form.

 

Written informed consent and assent were obtained from each study participant for the publication of this work.

 

 

Characteristics of the Infected

 

We interviewed 73 Covid-19 cases and 73 controls. Among the cases, 21(28.8%) were males and 52 (71.2%) females and among the controls 20 (27%) male and 53 (73%) female. The median age of the respondents for cases was 15 years (Q₁=14; Q₃=16) and for controls was 14 years (Q₁=13; Q₃=16) Table 1. We found that 64(88%) had one or more symptoms lasting an average of 4.9 days (SD 1.4). Only one patient (1.3%) had symptoms severe enough to warrant admission and there were no fatalities.

 

Description of the outbreak by place

 

All six hostels at the school were affected Figure 1. The most affected were Angevine 22(30%), Winsdor 14(19%) and Tudor 13(18%) hostels. We found the average class had 39.8 (SD 13) against a capacity of 25 students per classroom. The boarding hostels were oversubscribed by 150% with 603 students against the maximum allowed capacity of 400.

 

Epidemic timeline

 

We noted the index case tested positive for Covid-19 on 18 November. The majority of cases fell ill on the 20th of November. The median incubation period was 3 days (Q₁=2; Q₃=5). The outbreak was multi-modal with peaks occurring on the 10^th, 12^th, 15^th, 16^th, 18^th, and 20^th of November 2020 Figure 2. After all students had completed their isolation and quarantine period, the school was closed on 4 December 2020.

 

Factors associated with contracting SARS-2 at the School

 

On bivariate analysis students who had close contact with an infected patient were 26 times more likely to contract Covid-19 (OR 26.0 CI 95%10.8-62.6 p=0.00). Students who used recommended hand hygiene practices consistently were 52% protected (OR 0.48 95% CI 0.24-0.98 p=0.01). Consistently wearing face masks was 61% protective (OR 0.39 95% CI 0.20-0.78 p=0.01).

 

Independent factors associated with contracting SARS-CoV-2 (Severe Acute Respiratory Syndrome Corona Virus2)

 

We adjusted for age, sex, form, and boarding residency and the independent risk factor for contracting Covid-19 was close contact with the infected patient (aOR 26.6 95% CI 10.8-64.4, p=0.01), wearing face masks (aOR 0.42 95% CI 0.20-0.78 p=0.01) and following the recommended hand hygiene practices (aOR 0.4 95% CI 0.25-0.97, p=0.01) were independent protective factors Table 2.

 

Outbreak detection and response

 

The outbreak Rapid Response Team (RRT) was notified of the outbreak on 18 November and visited the school within 24hours. We conducted mass testing of all students and instituted a lockdown of the school; day scholar classes were suspended. All positive cases were moved to two hostels.

 

 

We sought to investigate the outbreak to determine the factors associated with contracting Covid-19 at a High School. Our main findings were students who had close contact with an infected patient were more likely to contract Covid-19. These findings were similar to the study done by Bi et al., [12] in Shanghai, who found that the spread of Covid-19 was attributed to the close interactions among family members. The school was overcrowded this could be a possible explanation for the rapid spread of the virus at the school. James et al. also found high attack rates among congregants who attended church gatherings that were not compliant with social distancing guidelines [13]. Kedebe et al., also noted that practices such as hugging and shaking hands were risk factors for contracting Covid-19 [14].

 

Based on our findings, we rejected the null hypothesis, following hand hygiene practices such as handwashing with soap and water and consistent use of hand sanitizer indicate knowledge of the Covid-19 infection prevention and control measures [15, 16]. A study by Mamdooh et al., found hand hygiene a significant protective factor in preventing the spread of Covid-19 [17]. In addition, we found the use of face masks was noted to be protective against Covid-19. Howard et al., noted similarly that medical masks reduced the transmission of Covid-19 among nurses [18]. We found in the immediate aftermath of these measures no student at the school turned positive [19], however more studies in school settings need to be done.

 

We noted that during the investigation, 98% of the cases had mild disease and all recovered within 5 days. The European Center for Disease Control (ECDC) report on Covid-19 noted in schools, young people have mild disease [20] with no symptoms. However, we found that 88% exhibited symptoms in contrast to several studies [1, 4, 12, 21-23] which noted between 71-85% of the Covid-19 cases were asymptomatic. There is need to conduct further studies on this.

 

Limitations

 

We encountered communication barriers with 6(8.2%) cases who had hearing and speech impairment. We employed a sign language teacher to administer the questionnaire. The language barrier might have led to some information being lost in translation.

 

 

We found that close contact with an infected patient was an independent risk factor for contracting Covid-19 and the school was overcrowded. Following recommended hand hygiene practices and wearing face masks were independent protective factors. We imposed strict isolation of all cases and quarantined all their close contacts, we increased the handwashing facilities from 1 per hostel to 8-10 per hostel and reduced the intake of new students. This proved to be effective in controlling the spread of Covid-19 as there were no positive cases reported after these measures.

 

 

The authors declare no competing interests whether financial and non-financial.

 

Funding

 

This study was funded by Mashonaland West PMD (Provincial Medical Directorate) and Health Studies Office.

 

 

KM, DB, TD, GM, EG, NG, TJ and MT: conception, design, acquisition, data collection, analysis and interpretation of data. KM and BD wrote the first draft of the manuscript. EG, NG, TJ and MT critically revised the draft for important intellectual content. All authors read and approved the final manuscript.

 

 

We would like to acknowledge the study participants, Provincial Medical Director-Mashonaland West, Mashonaland West PHE, District Health Executive- Makonde, The Headmistress of the High School, the High School Executive and Health Studies Office for making our study a success.

 

 

Table 1: Demographics of study participants

Table 2: Independent Factors for Contracting Covid-19 at A High School

Figure 1: A High School Spot Map

Figure 2: A High School Covid-19 Outbreak Epi-curve

 

 

1. Epidemiology Working Group for NCIP Epidemic Response, Chinese Center for Disease Control and Prevention.The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) in China . Zhonghua Liu Xing Bing Xue Za Zhi [Internet]. 2020 Feb 10 [cited 2023 Jul 26];41(2):145-5 Chinese. https://doi.org/10.3760/cma.j.issn.0254-6450.2020.02.003 Click on "English Abstract". PubMed | Google Scholar


2. Bogoch II, Watts A, Thomas-Bachli A, Huber C, Kraemer MUG, Khan K. Pneumonia of unknown aetiology in Wuhan, China: potential for international spread via commercial air travel . Journal of Travel Medicine [Internet]. 2020 Jan 14 [cited 2023 Jul 26];27(2):taaa008 [3p.]. https://doi.org/10.1093/jtm/taaa008 PubMed | Google Scholar


3. Hollander JE, Carr BG.Virtually perfect? Telemedicine for COVID-19 . N Engl J Med [Internet]. 2020 Apr 30 [cited 2023 Jul 26];382(18):1679-81. https://doi.org/10.1056/nejmp2003539 Google Scholar


4. Fauci AS, Lane HC, Redfield RR.COVID-19- Navigating The Uncharted . N Engl J Med [Internet]. 2020 Mar 26 [cited 2023 Jul 26];382(13):1268-9. English, Chinese. https://doi.org/10.1056/NEJMe2002387 Google Scholar


5. World Health Organization. Pneumonia of Unknown Cause- China [Internet]. Geneva, Switzerland: World Health Organisation; 2020 Jan 5 [cited 2023 Jul 26].


6. World Health Organization.Weekly epidemiological update - 17 November 2020 [Internet]. Geneva, Switzerland: World Health Organization; 2020 Nov 17 [cited 2023 Jul 26].


7. Ministry of Health and Child Care.Zimbabwe Covid-19 Situation Report, 24 November 2020 [Internet]. Harare, Zimbabwe: Ministry of Health and Child Care; 2021 Jan 28 [cited 2023 Jul 26].


8. Pan American Health Organization (PAHO)/WHO.Case definitions for COVID-19 Surveillance [Internet]. Washington DC, USA: PAHO/WHO; 2020 Aug 7 [cited 2023 Jul 26].


9. Song JW, Chung KC.Observational Studies: Cohort and Case-Control Studies: Plast Reconstr Surg [Internet]. 2010 Dec [cited 2023 Jul 26];126(6):2234-42. https://doi.org/10.1097/prs.0b013e3181f44abc PubMed | Google Scholar


10. Ssebuufu R, Sikakulya FK, Mambo SB, Wasingya L, Nganza SK, Ibrahim B, Kyamanywa P.Knowledge, Attitude, and Self-Reported Practice Toward Measures for Prevention of the Spread of COVID-19 Among Ugandans: a Nationwide Online Cross-Sectional Survey . Front Public Health [Internet]. 2020 Dec 15 [cited 2023 Jul 26];8: 618731. https://doi.org/3389/fpubh.2020.618731 PubMed | Google Scholar


11. Bi Q, Wu Y, Mei S, Ye C, Zou X, Zhang Z, Liu X, Wei L, Truelove SA, Zhang T, Gao W, Cheng C, Tang X, Wu X, Wu Y, Sun B, Huang S, Sun Y, Zhang J, Ma T, Lessler J, Feng T. Epidemiology and Transmission of COVID-19 in 391 Cases and 1286 of Their Close Contacts in Shenzhen, China: a Retrospective Cohort Study . The Lancet Infectious Diseases [Internet]. 2020 Apr 27[cited 2023 Jul 26];20(8):911-9. https://doi.org/10.1016/S1473-3099(20)30287-5 Erratum in Lancet Infect Dis. 2020 Jul;20(7):e148-e179. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30369-8/fulltext https://doi.org/10.1016/S1473-3099(20)30369-8 PubMed | Google Scholar


12. James A, Eagle L, Phillips C, Hedges DS, Bodenhamer C, Brown R, Wheeler JG, Kirking H.High COVID-19 Attack Rate Among Attendees at Events at a Church - Arkansas, March 2020 . MMWR Morb Mortal Wkly Rep [Internet]. 2020 May 22 [cited 2023 Jul 26];69(20):632-5. https://doi.org/10.15585/mmwr.mm6920e2 Google Scholar


13. Kebede Y, Yitayih Y, Birhanu Z, Mekonen S, Ambelu A. Knowledge, perceptions and preventive practices towards COVID-19 early in the outbreak among Jimma university medical center visitors, Southwest Ethiopia . PLoS ONE [Internet]. 2020 May 21 [cited 2023 Jul 26];15(5):1-15. https://doi.org/10.1371/journal.pone.0233744 PubMed | Google Scholar


14. Maunder R, Lancee W, Balderson K, Bennett J, Borgundvaag B, Evans S, Fernandes C, Goldbloom D, Gupta M, Hunter J, McGillis Hall L, Nagle L, Pain C, Peczeniuk S, Raymond G, Read N, Rourke S, Steinberg R, Stewart T, VanDeVelde-Coke S, Veldhorst G, Wasylenki D.Long-term Psychological and Occupational Effects of Providing Hospital Healthcare During SARS Outbreak . Emerg Infect Dis [Internet]. 2006 Dec [cited 2023 Jul 26];12(12):1924-32. https://doi.org/10.3201/eid1212.060584 PubMed | Google Scholar


15. Gill CJ, Galea S. A conceptual framework for reopening our society during the Covid-19 pandemic . F1000Res [Internet]. 2020 Jun 8 [cited 2023 Jul 26];9:572. https://doi.org/10.12688/f1000research.24352.1 PubMed | Google Scholar


16. Alzyood M, Jackson D, Aveyard H, Brooke J.COVID-19 reinforces the importance of handwashing . Journal of Clinical Nursing [Internet]. 2020 Apr 27 [cited 2023 Jul 26];29(15-16):2760-1. https://doi.org/10.1111/jocn.15313 PubMed | Google Scholar


17. Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, Van Der Westhuizen HM, Von Delft A, Price A, Fridman L, Tang LH, Tang V, Watson GL, Bax CE, Shaikh R, Questier F, Hernandez D, Chu LF, Ramirez CM, Rimoin AW. An evidence review of face masks against COVID-19 . Proc Natl Acad Sci USA [Internet]. 2021 Jan 26 [cited 2023 Jul 27];118(4): e2014564118 [12 p.]. https://doi.org/10.1073/pnas.2014564118 Google Scholar


18. Roxby AC, Greninger AL, Hatfield KM, Lynch JB, Dellit TH, James A, Taylor J, Page LC, Kimball A, Arons M, Schieve LA, Munanga A, Stone N, Jernigan JA, Reddy SC, Lewis J, Cohen SA, Jerome KR, Duchin JS, Neme S. Detection of SARS-COV-2 Among Residents and Staff Members of an Independent and Assisted Living Community for Older Adults- Seattle, Washington, 2020 . MMWR Morb Mortal Wkly Rep [Internet]. 2020 Apr 10 [cited 2023 Jul 26];69(14):416-18. https://doi.org/10.15585/mmwr.mm6914e2 PubMed | Google Scholar


19. European Centre for Disease Prevention and Control. COVID-19 in Children and the Role of School Settings in COVID-19 Transmission [Internet]. Stockholm, Sweden: European Centre for Disease Prevention and Control; 2020 Aug 6 [cited 2023 Jul 26].


20. Rothan HA, Byrareddy SN. -The epidemiology and pathogenesis of coronavirus disease (COVID-19) outbreak . J Autoimmun [Internet]. 2020 Feb 26 [cited 2023 Jul 26];109: 102433 [4 p.]. https://doi.org/10.1016/j.jaut.20102433 PubMed | Google Scholar


21. Romero Starke K, Petereit-Haack G, Schubert M, Kämpf D, Schliebner A, Hegewald J, Seidler A. The Age-Related Risk of Severe Outcomes due to COVID-19 infection: a Rapid Review, Meta-Analysis, and Meta-Regression . IJERPH [Internet]. 2020 Aug 17 [cited 2023 Jul 26];17(16):5974. https://doi.org/10.3390/ijerph17165974 PubMed | Google Scholar


22. Liu T, Liang W, Zhong H, He J, Chen Z, He G, Song T, Chen S, Wang P, Li J, Lan Y, Cheng M, Huang J, Niu J, Xia L, Xiao J, Hu J, Lin L, Huang Q, Rong Z, Deng A, Zeng W, Li J, Li X, Tan X, Kang M, Guo L, Zhu Z, Gong D, Chen G, Dong M, Ma W. Risk Factors Associated with COVID-19 Infection: a Retrospective Cohort Study Based on Contacts Tracing . Emerg Microbes Infect [Internet]. 2020 Jul 7 [cited 2023 Jul 26];9(1):1546-53. https://doi.org/10.1080/22221751.2020.1787799 PubMed | Google Scholar


23. Roxby AC, Greninger AL, Hatfield KM, Lynch JB, Dellit TH, James A, Taylor J, Page LC, Kimball A, Arons M, Munanga A, Stone N, Jernigan JA, Reddy SC, Lewis J, Cohen SA, Jerome KR, Duchin JS, Neme S. Outbreak Investigation of COVID-19 Among Residents and Staff of an Independent and Assisted Living Community for Older Adults in Seattle, Washington . JAMA Intern Med [Internet]. 2020 May 21 [cited 2023 Jul 26];180(8):1101-1105. Available from: https://doi.org/10.1001/jamainternmed.2020.2233 PubMed | Google Scholar