Critical Insights into the Fourth COVID Wave in Kenya and Model Scenarios
Dilemma and decisions amid a long streak of high positivity rates
Nashon J. Adero1 day ago·6 min read
The more contagious variants make it necessary to expect faster change cycles, hence the pragmatism of weekly monitoring and updates of the COVID-19 models used for calibrating containment policies and strategies.
The long streak of positivity rates in Kenya has persisted since June 9, 2021. The more contagious Delta variant must be a key part of the explanation.
As of August 11, 2021, there was still no sign of the curve flattening any time before October 2021.
The model scenarios project between 278,000 and 287,000 cases come October 1, 2021. This is a worrying trend that implies a daily average of at least 1,200 in new cases between August 11 and October 1, 2021.
Kenya must confront COVID-19 containment challenges with a strong dimension of data-driven timing and decisions based on scientific evidence.
The recent radical relaxation of COVID-19 restrictions by government should be treated as adventures meant to inform open-minded learning with a readiness to own up to mistakes and reverse action. They must not be final decisions impervious to the flow of evidentiary pointers to a radical reversal of previous policy action.
As of August 11, 2021 the total cases globally had exceeded 205 million with a global positivity rate of 2.1% and a recovery rate of 90%. These hitherto steady metrics reflect the general trend across the world. In Africa, the case fatality rate has been 2.5% with a recovery rate of 88%. South America has maintained the highest case fatality rate of 3.1%.
As discussed extensively in the previous article in this research and modelling series, the likelihood of developing severe (serous or critical) cases out of all the reported COVID-19 cases is the more fluid metric that countries that have not vaccinated a sufficient percentage of their populations — hence still far from herd immunity, need to monitor closely. These severe cases require HDU and ICU care. This position has been vindicated as severe cases rise.
In less than two weeks, the probability of developing severe cases has changed substantially in the countries and regions with low vaccination penetration rates. Europe (at 0.018%) has maintained the lowest probability of developing such severe cases of late, followed by North America (0.053% as of August 11). As of August 11, the global average on this metric was 0.049%, with 0.060% in Asia, 0.064% in Africa, 0.069% in South America, and 0.117% in Oceania. Vaccine hesitancy and apathy can only aggravate the unwelcome changes in this critical metric. As Kenya registered 0.063% on this metric as of August 11, Uganda was still leading in East Africa with more than 0.6%. This was ten times Kenya’s probability measure on the likelihood of developing severe cases.
Latest Developments in Kenya, New Challenges
Ranking seventh in Africa’s league table of the highest number of COVID-19 cases, Kenya had reported a total of 215,730 COVID-19 cases as at August 11, 2021. The corresponding metrics in Kenya, a representative of African countries struggling with the Delta variant and a fourth wave amid constraints on vaccine supply, have of late been a case fatality rate of 2.0% and a recovery rate of 92%. The country has witnessed cases of dilemma and at times decisions that in the eyes of scientists and researchers appear to be rushed. The recent removal of distancing restrictions on public transport is a key example. How can we find the balancing point?
The country has been recording a long streak of high positivity rates, far above 5%. This modelling series traced the recent surge all the way from June 9, with another key development in the surge from July 31, 2021 — when the positivity rate jumped to 15.6%. From June 9 to August 11, the compact model assuming the continuation of the business-as-usual (BAU) spread of the Delta variant maintained a prediction of within 1% of the reported actual cases. The positivity rate above 17% recorded on August 5 later saw the actual trend going beyond the BAU scenario.
Notably, an exponential trend in the growth of cases emerged from July 31, 2021. Up to August 11, the reported cases have remained within less than 1% of the model-predicted figures along the simulated exponential growth equation with a daily growth rate of about 0.56%, y=P*e^(0.0056t), P being the cumulative number of reported cases on July 31 and t the interval in days since July 31, 2021.
As of August 11, though, there was still no sign of the curve flattening any time before October 2021.
Key insights can be drawn based on two projected scenarios here that sandwich a compact bandwidth of the likely trends: an exponential growth scenario from July 31 and a BAU scenario from June 9, 2021. Respectively, the scenarios project 286,559 and 278,118 cases come October 1, 2021. This is a worrying trend that implies a daily average of at least 1,200 in new cases between August 11 and October 1, 2021.
Applying the 0.06% — 0.09% probability range for severe cases as already established in this modelling series for Kenya since the Delta variant began ravaging the country, these projections imply between 165 and 260 serious or critical cases by October 2021, which would require HDU and ICU care.
Before the confirmation of the Delta variant in Kenya, it used to take 3–4 weeks for these mathematical models to be updated to accommodate new trends. The more contagious variants make it necessary to expect faster change cycles, hence the pragmatism of weekly monitoring and updates of the COVID-19 models used in this series for calibrating containment policies and strategies.
Shared Visual Evidence through COVID Heat Maps
The map of COVID-19 cases by shares of the national tally across the Kenyan counties has also been changing since the Delta variant started spreading from the western city of Kisumu, where it was first confirmed in Kenya. The share of cases in Kisumu County reduced from 3.2% in June to 2.9% in August. Kilifi County has realised a jump from 2.3% to 2.6% over the same period. This outcome can largely be explained by the containment measures that were recently applied in the western part of Kenya.
The emerging and compelling message is that containment measures, in the form of restrictions on movements and mass gatherings, do work. They are, consequently, an essential strategy to back up the slow vaccination rate, occasioned by the supply constraints that lie beyond the systems boundary under Kenya’s control.
Further easing of restrictions and cessation of mask-wearing are, therefore, likely to lead to a substantial rise in cases within a week or two, as the more contagious Delta variant has already demonstrated.
The long streak of high positivity rates and surging cases in Kenya, since June 9, 2021, calls for extra caution and expedited timing, testing, tracing, and vaccination rates. Henceforth, the COVID-19 containment challenges Kenya must confront have a strong dimension of data-driven timing and decisions based on scientific evidence.
The recent radical relaxation of COVID-19 restrictions the government has implemented should be treated as adventures meant to inform open-minded learning with a readiness to own up to mistakes and reverse action, rather than final decisions impervious to any new evidence pointing to a justified reversal of any policy decisions gone wrong or with unintended consequences.
With dedicated monitoring of new developments and swift action, new evidentiary revelations for radical changes could be realised for appropriate action in a matter of weeks. The dilemma still lingering on mask-wearing in the USA and Europe after vaccinating the majority of their citizens is just one of such points on the learning curve of a world challenged by a pandemic. Kenya has much to learn from such experiences as the fourth wave rages on. Nashon J. Adero
A geospatial and systems modelling expert, lecturer, youth mentor and trained policy analyst, who applies system dynamics to model complex adaptive systems. NASHON J. ADERO FOLLOWS
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