Nigeria

Epidemiological comparison of the first and second waves of the COVID-19 pandemic in Nigeria, February 2020–April 2021

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Oluwatosin Wuraola Akande, Kelly Osezele Elimian, Ehimario Igumbor, Lauryn Dunkwu, Chijioke Kaduru, Olubunmi Omowunmi Olopha, Dabri Olohije Ohanu, Lilian Nwozor, Emmanuel Agogo, Olusola Aruna, Muhammad Shakir Balogun, Olaolu Aderinola, Anthony Ahumibe, Chinedu Arinze, Sikiru Olanrewaju Badaru, William Nwachukwu, Augustine Olajide Dada, Cyril Erameh, Khadeejah Hamza, Tarik Benjamin Mohammed, Nnaemeka Ndodo, Celestina Obiekea, Chinenye Ofoegbunam, Oladipo Ogunbode, Cornelius Ohonsi, Ekaete Alice Tobin, Rimamdeyati Yashe, Afolabi Adekaiyaoja, Michael C. Asuzu, Rosemary Ajuma Audu, Muhammad Bashir Bello, Shaibu Oricha Bello, Yusuf Yahaya Deeni, Yahya Disu, Gbenga Joseph, Chidiebere Ezeokafor, Zaiyad Garba Habib, Christian Ibeh, Ifeanyi Franklin Ike, Emem Iwara, Rejoice Kudirat Luka-Lawal, Geoffrey Namara, Tochi Okwor, Lois Olajide, Oluwafunke Olufemi Ilesanmi, Solomon Omonigho, Ferdinand Oyiri, Koubagnine Takpa, Nkem Usha Ugbogulu, Priscilla Ibekwe, John Oladejo, Elsie Ilori, Chinwe Lucia Ochu, Chikwe Ihekweazu

Abstract

Background

With reports of surges in COVID-19 case numbers across over 50 countries, country-level epidemiological analysis is required to inform context-appropriate response strategies for containment and mitigation of the outbreak. We aimed to compare the epidemiological features of the first and second waves of COVID-19 in Nigeria.

Methods

We conducted a retrospective analysis of the Surveillance Outbreak Response Management and Analysis System data of the first and second epidemiological waves, which were between 27 February and 24 October 2020, and 25 October 2020 to 3 April 2021, respectively. Descriptive statistical measures including frequencies and percentages, test positivity rate (TPR), cumulative incidence (CI) and case fatality rates (CFRs) were compared. A p value of <0.05 was considered statistically significant. All statistical analyses were carried out in STATA V.13.

Results

There were 802 143 tests recorded during the study period (362 550 and 439 593 in the first and second waves, respectively). Of these, 66 121 (18.2%) and 91 644 (20.8%) tested positive in the first and second waves, respectively. There was a 21.3% increase in the number of tests conducted in the second wave with TPR increasing by 14.3%. CI during the first and second waves were 30.3/100 000 and 42.0/100 000 respectively. During the second wave, confirmed COVID-19 cases increased among females and people 30 years old or younger and decreased among urban residents and individuals with travel history within 14 days of sample collection (p value <0.001). Most confirmed cases were asymptomatic at diagnosis during both waves: 74.9% in the first wave; 79.7% in the second wave. CFR decreased during the second wave (0.7%) compared with the first wave (1.8%).

Conclusion

Nigeria experienced a larger but less severe second wave of COVID-19. Continued implementation of public health and social measures is needed to mitigate the resurgence of another wave.