Officers from the Ministry of Health carrying out Fumigation and COVID-19 Mass Testing. Photo/ Courtesy.
Officers from the Ministry of Health carrying out Fumigation and COVID-19 Mass Testing. Photo/ Courtesy.

The World Health Organization, WHO, has issued a statement regarding the recent decline in cases of covid-19 in Kenya. Here is the full presser;

 WHO Kenya Statement on the recent decline of COVID-19 cases in Kenya

Since 13 March 2020, when Kenya reported its first confirmed COVID-19 case, the country has progressively witnessed an increase in number of cases and a widening of geographical scope of infection.

There were 34,057 confirmed cases as on 30 August 2020, and all 47 counties had reported cases with Nairobi and Mombasa counties having highest attack rates of 441 and 196 cases per 100,000 population respectively. The country had tested and reported on a cumulative total of 438,712 samples.

Over the past three weeks, there has been an apparent progressive decline in number of total nationally confirmed symptomatic and asymptomatic individuals. This decline closely mirrors trends for Nairobi and Mombasa counties which account for 64 % of the total cases.

However, this potentially may mask the national picture, as other counties are experiencing increasing case numbers.

During the same period of decline, a decline in number of laboratory tests being conducted has also been noted.

It was observed that the Kenyan testing strategy was not adhered to during the period and wider targeted low risk groups were tested. Some laboratories supporting specific counties reported shortage of test kits and or specimen collection kits and therefore conducted limited tests for suspected cases and their contacts.

There has also been reduced effective contact tracing recently, again resulting in fewer cases being found.

The decline in total number of cases and the decline of weekly laboratory test positivity rate, from a high of 13 % in week 31 to current rate of 7 %; (the overall positivity rate has remained at 7.9 %) thus coincided with several factors including low laboratory tests, shortage of laboratory test kits, deviance from the national testing strategy and minimal contact tracing over the past three weeks.

This decline in weekly symptomatic individuals tested and positivity rate at national level has elicited discussion on whether it is an indication of a reduction of disease transmission and flattening of curve in Kenya and the subsequent implications on adjustment of public health interventions and social measures put in place to mitigate infection.

In respect of the easing of travel and social restrictions, WHO globally has issued criteria to guide health authorities and decision makers to determine level of COVID-19 control.

The criteria are grouped into three domains that should be evaluated to address three main questions:
1. Epidemiology-Is the epidemic controlled?
2. Health system-Is the health system able to cope with a resurgence of COVID-19 cases that may arise after adapting some measures?
3. Public Health Surveillance-Is the public health surveillance system able to detect and manage the cases and their contacts, and identify a resurgence of cases?

The criteria are not prescriptive, and it may not be feasible to answer some of them owing to lack of data, for instance. To the extent possible, countries should focus on the criteria most relevant for them to inform decision making. The thresholds are indicative and may need to be revisited as further information about the epidemiology of COVID-19 becomes available.

It is recommended to systematically assess the criteria at least weekly at a subnational administrative level when feasible. All three domains have further criteria and indicators to measure if they have been reached.

The epidemiology criteria for epidemic control include amongst others:
1. Decline of cases at least 50 % over a 3-week period since the latest peak and continuous decline in the observed incidence of confirmed and probable cases.

2. Less than 5 % of samples positive for COVID-19, at least for the last 2 weeks. It should be emphasized that the 5 % threshold applies only to a situation where widespread lab testing of all population groups and strata are included. As long as lab testing is focused on certain groups of the population, the positivity rate threshold cannot be extrapolated to the entire population. It should not be seen as the only or the most important criteria in this domain.

3. At least 80 % of cases are from contact lists and can be linked to known clusters
4 Decline in in the number of deaths among confirmed and probable cases at least for the last 3 weeks.

5. Continuous decline in the number of hospitalization and ICU admissions of confirmed and probable cases at least for the last 2 weeks.

On the apparent decline, the total confirmed cases declined by more than 50 % over the 3-week period of week 31-34 and lab test positivity dropped from 12 % to 7 % over the same period. While these are encouraging quality indicators that may be used as proxy to decreased transmission, the findings should be treated with caution.

Testing needs to be strengthened to capture a greater proportion of suspected cases within the testing regimen.

On the decline in the positivity rate, observations at the sub-national level indicates that over the above period of week 31-34, the general positivity trend for Nairobi county has been on a decline. Mombasa county has had a positivity rate of less than 5 % for most of the period of week 31-14.

Counties with areas constituting the larger Nairobi Metropolitan area including Kiambu, Kajiado and Machakos have had variable but higher positivity rates.

Based on the positivity rate, is this an indication then that the epidemic is controlled in Nairobi and Mombasa?

As encouraging as the reports may be, this cannot be stated conclusively, since the positivity rate can be interpreted only with comprehensive surveillance and testing of suspected cases. In addition, other epidemiological as well as health systems and public health surveillance considerations needs to be factored in deciding whether decline implies interruption of transmission and necessitation of review of interventions.

Again, this criteria should not be seen in isolation, and requires widespread testing (currently not in place) to be able to interpret this indicator.

There has also been minimal contact tracing in the recent past among the top 10 counties with highest burden of disease. Fifty-eight percent of the cases have pending, incomplete contact tracing and only 129 positive contacts were reported from  August 1 to 23rd August 2020. In Nairobi 42 % of cases were pending contact listing, while over 90 % were pending in Kiambu, Machakos, Mombasa, Kajiado, Busia and Nakuru Counties.

The trends in COVID-19 mortality are also being monitored in order to ascertain whether there is a decline in number of deaths among confirmed or probable cases in a minimum duration of 2 weeks. With a 3-week lag time, a decline in deaths will indicate total number of cases decreasing. A continuous decline for at least 2 weeks in number of hospitalizations ICU admissions of confirmed and probably cases needs to be demonstrated.

As at week 34, 554 COVID-19 deaths had been reported nationally Deaths in the communities have been reported in various counties; some of these deaths have not been documented in daily reporting.

There was a decline in hospital admissions in Nairobi from 470 at the end of week 31 to 215 in week 34. For Mombasa, this flattened at about 59 admissions per day for most of August. There was no decline in other counties.