State unaware of coronavirus prevalence

The government does not know the prevalence of Covid-19 nationally even as more people tested positive for the disease, with the cases now standing at 5,533 yesterday.

Lack of such crucial information raises serious questions about the modeling being used to determine the number of deaths, and those who will be infected if the government eases the current restrictions on travel and social gatherings.

The model that prompted President Uhuru Kenyatta to extend the night curfew and prohibit travel from counties considered virus hot spots had shown that 45,000 people would die and 450,000 would be infected if restrictions were eased by 60 per cent.

But the admission by the Health ministry that it is still in the dark on this key metric casts doubt on the veracity of this information.

A Health official said the Kenya Medical Research Institute will conduct serological tests across the population to determine how widespread the disease is. However, no timelines were given.

Health Chief Administrative Secretary Rashid Aman said the current tests being carried out cannot tell how far the disease has spread.

This is despite confirmation that the disease is now in 40 counties, with a high possibility that there are undiagnosed cases in the remaining seven counties because the government has not done mass or targeted testing.

“The testing we are doing is more or less a targeted one in which we respond to certain vulnerable spots in an area so it might not give a total picture of the disease in the country,” said Dr Aman.

He added: “In the particular areas where we focus, the targeted mass testing will tell us the prevalence.”

Part of the reason the prevalence of the disease is unknown could be the fact that the actual number of persons tested for it is not known.

Tests so far

By yesterday, the government had conducted 158,404 tests. Out of these, 3,090 were behind the newest 149 cases. Five people dead from the virus, raising the fatalities to 137.

Aman explained that the test for checking for prevalence is different from the one used to diagnose the disease.

Diagnosis of the disease is done using the Real Time-Polymerase Chain Reaction, also known as RT-PCR tests, while prevalence can be checked using a rapid diagnosis test (RDT).

While the ministry has confirmed that it has RDT test kits, none has been approved for Covid-19 because the World Health Organisation recognises RT-PCR tests as the gold standard for diagnosis the coronavirus disease.

RDT, therefore, can only be used for surveillance and research on coronaviruses.

“The test for prevalence is meant to find out how many people have been exposed to the disease. You can get this by doing an antibody test which checks for the response of the immune system,” said Aman.

Detecting antibodies

The antibody test determines this by detecting antibodies in the blood. If your test comes back positive, it means you were once infected by the virus and developed antibodies against it.

But if the result is negative, then you have never had the coronavirus disease.

The tests, however, are not 100 per cent dependable. A recent study published on June 18 in the Nature Medicine journal says the antibodies usually clear out of the body after three months.

Up to 80 per cent of the cases in the country are asymptomatic or mildly symptomatic, which means these individuals will pass as normal and healthy.

This could also mean that majority of Kenyans are infected but are yet to be tested to confirm their status.