Africa could see up to 450,000 people test positive for the highly infectious Coronavirus (Covid-19) by the second week of May, putting the continent's fragile health systems under severe test.
A team of scientists from the London School of Hygiene and Tropical Medicine made the prediction based on a mathematical modelling projection, as the number of Covid-19 positive Africans more than doubled in one week to Friday's figure of more than 6,500 cases.
The scientists also project that each East African country will report at least 10,000 Covid-19 cases by May 10, with Uganda being the last to hit this number.
With 50 out of 56 African countries now reporting Covid-19 cases, the scientists say only strict interventions such as social distancing could make their forecasts wrong.
"We are only projecting reported cases, which are a fraction of actual cases. Ramping up testing, while better for the overall response and the ultimate number of actual cases, would mean seeing more cases sooner," said Carl Pearson the principal investigator of a paper published on March 25.
The number of coronavirus positive people globally crossed the one million mark on Friday.
More than 53,000 had died from the global pandemic, while 213,000 had recovered. The US had, by far, the highest number of positive cases numbering more than 225,000 on Friday, while Italy's death toll of nearly 14,000 remains the highest globally.
Within the East African Community, Kenya had the highest tally of 122 Covid-19 cases as at Friday, while South Sudan was yet to report a single case.
The scientific paper, titled Projection of Early Spread of Covid-19 in Africa, estimates the timing for the first 1,000 and first 10,000 coronavirus positive cases for 45 African countries that had reported at least one case within its borders.
Using the Susceptible-Exposed-Infectious-Recovered (SEIR) predictive modelling used to forecast the Covid-19 outbreak within and outside of China based on daily observations, scientists the world over are trying to forecast the effect of the disease in continents that are now experiencing exponential spread of infections.
In the US, for example, the White House coronavirus task force has presented a grim picture of where America could be heading over the next two months, even with interventions like physical distancing. The task force projects 100,000 to 240,000 deaths from the virus, even with mitigation measures in place.
Health experts, including the Africa Centres for Diseases Control (Africa CDC), have expressed concern that the continent has not yet scaled its capacity to capture all the Covid-19 cases.
Increased testing could see the numbers rise exponentially in the coming weeks, as has happened in the US and Europe.
"Alarmingly, these are largely synchronised and continent--wide. The real burdens are certainly higher. This calls for urgent action across Africa," the scientists note.
Going by these estimates and global death rates of between 0.5-1 per cent of cases, typically within two to three weeks after the onset of symptoms, between 2,250 and 4,500 Africans could die from the disease.
"We can say that there will be many knock-on negative healthcare outcomes like disruption of normal medical care for non-Covid-19 patients, disruption of preventative activities like vaccine campaigns, which will be worse if the pandemic isn't well managed. Figuring out the cost of all this, plus the economic disruption due to necessary control activities, will be an enormously complex task," added Mr Pearson.
Africa CDC director John Nkengasong says the number of infections on the continent could be much higher than what has been reported.
Speaking to journalists in a web interview on Thursday, the virologist said that the next few weeks will be crucial in determining if the pandemic will be mild, moderate or severe in Africa.
"We will have a clearer picture of the extent of infections in two to three weeks, but the severity of the pandemic will be dependent on whether there are community infections particularly in the slums and rural areas in respective countries," said Dr Nkengasong.
The past month has seen an increase in infections in African countries and within different localities in the hardest-hit countries.
In the Democratic Republic of Congo, for instance, the World Health Organisation (WHO) says whereas Covid-19 cases were at first confined to Kinshasa, a handful have been reported in the eastern-most regions of the country that were until recently in the grip of an Ebola outbreak.
In South Africa, all provinces have now reported cases. The outbreaks in Burkina Faso, Cameroon and Senegal are also widespread.
"Case numbers are increasing exponentially in the African region. It took 16 days from the first confirmed case to reach 100 cases. It took a further 10 days to reach the first thousand. Three days after this, there were 2000 cases, and two days later we were at 3000," said Matshidiso Moeti, the WHO regional director for Africa.
Projections of the number of people who could get infected with Covid-19, and how many it may ultimately kill, change by the day.
To the general public, these ranges demonstrate the potential impact of not adhering to social distancing guidelines that scientists say substantially reduce the number of infections and stem the flow of patients that could overwhelm healthcare facilities.
Hospital systems and policymakers also use these estimates to prepare the intensive care unit beds, emergency room capacity, and ventilators required to support the sick.
Given the different dynamics between Europe, Asia, America, and Africa, Mr Pearson says that countries need to develop people-and-place specific interventions and find detailed solutions that work for their circumstances. "We hope those that succeed will share those lessons with their neighbours," he said.
To contain Covid-19, many countries in Africa are implementing measures that restrict gatherings and the movement of people. Nationwide lockdowns and curfews are in effect in Kenya, Uganda, the Republic of the Congo and other countries.
"However, governments must use these measures in a considered, evidence-based manner, and make sure that people can continue to access basic necessities," Dr Moeti added.