COVID-19 pandemic in the African continent: forecasts of cumulative cases, new infections, and mortality

Yohannes Kinfu; Uzma Alam; Tom Achoki

Short Title: a a n d t h e C O V I D -1 9 p a n d e m i c A f r i c a a n d t h e C O V I D -1 9 p a n d e m i c C O V I D -1 9 p a n d e m i c i n t h e A f r i c a n c o n t i n e n t : f o r e c a s t s o f c u m u l a t i v e c a s e s , n e w i n f e c t i o n s , a n d m o r t a l i t y A f r i c a a n d t h e C O V I D -1 To date, no vaccine or effective treatment is available for COVID-19. Therefore, the ability to minimise the devastating consequences of the disease on people's lives and livelihoods relies on the implementation of effective preventative non-pharmaceutical interventions (NPIs). NPIs include multiple public health measures designed to reduce viral transmission rates in a population by reducing the reproduction number (R 0 ); the average number of secondary cases each case generates. (4) (5) (6) NPIs directly influence the course of the COVID-19 pandemic, including the rate of spread, and the expected duration of the pandemic. However, several characteristics of the virus remain ambiguous or mostly unknown, (7) (8) such as the incubation period (the time between infection and symptom onset), serial interval (the time between symptom onset of a primary and secondary case) the extent of asymptomatic cases, the possibility of pre-symptomatic infectiousness, the case fatality rate (CFR), and also the possible role of weather in transmission. Estimates for COVID-19 CFR range from 0.3-1%. (9) Asymptomatic or mild presentation comprises the bulk of the reported cases, which is an estimated at 80%. (10) Longitudinal viremia measurements from a small study (sample size of 16) , suggests that there are high enough viral loads to trigger pre-symptomatic infectiousness for 1-2 days before the onset of symptoms. (11) With the lack of clinical studies measuring viremia, the infectious period also remains largely unknown, with estimates ranging from few days to 10 days or more after the incubation period. (11) The complexity of the infection and recovery process, therefore, means that proper understanding of the epidemiological dynamics of COVID-19 within the local context is fundamental to combat the pandemic. Studies illustrating future trajectories of the disease are not only helpful to develop early warning systems, avoid overwhelming healthcare services and minimize morbidity and mortality from the disease, but also assist countries to evaluate the effects of interventions and the long-term consequences of the virus on peoples' livelihood. This is particularly true in Africa, where livelihoods are fragile, and previous epidemics, such as HIV/AIDS and, more recently, Ebola, have been known to exert enormous socioeconomic consequences. (12) (13) (14) In addition, in the face of a new pandemic in the region, the already overstretched healthcare systems that are struggling to deliver essential healthcare services such as immunization and HIV/AIDS treatment would be in further jeopardy and at risk of losing the gains achieved so far in disease control efforts. This study, using a robust methodology, provides spatial and temporal trajectories of COVID-19 for the entire Africa region. To the best of our knowledge, this is the first such attempt and accounts for the local context and characteristics relevant to the epidemiology of the diseases in the region.