Photo: Kennyjo

COVID-19 Might Be Severely Underdiagnosed in Venezuela

The Chinese-made antibody tests bought by many countries, including Venezuela, aren’t recommended to detect cases before they become acute.

One of the main features of the Maduro regime during these pandemic times is its pride; just recently, it bragged about doing over 200,000 COVID-19 tests (the 15th country with more tests in the world), and it only found 227 positive cases. Peru for instance, has tested 143,000 people, detecting 15,000 positivesbecause the more tests you run, the more cases you should find. 

Unless you’re only using rapid tests.

A key intervention to tackle COVID-19 is increasing our testing capacity. This was done early on in countries like South Korea, and was key to limiting the spread of the disease. Unfortunately, it’s also very hard to do.

Currently, the preferred method to diagnose a suspicious patient with COVID-19 is a PCR test, a form of assay that detects the virus’s genetic material. PCR tests aren’t perfectthey can only detect about 85% of the people who are truly sick, and their validity relies heavily on strict protocols. They can’t be performed anywhere either, as they require complex and costly laboratory equipment.

Although several (and mostly private) labs around Venezuela can carry these assays, only the National Institute of Hygiene (INH) in Caracas is authorized to test for COVID-19.

But according to a recent report from Reuters, the INH can only run about 100 tests. This means the overwhelming majority of tests performed in Venezuela are rapid ones. Reuters also indicates that only positive rapid tests are being confirmed with PCR diagnosis.

PCR tests aren’t perfectthey can only detect about 85% of the people who are truly sick, and their validity relies heavily on strict protocols.

Rapid tests are generally cheaper and have the advantage of being easily incorporated into inexpensive, simple kits that can be used in any health center, or even a patient’s home, meaning they could allow countries to really scale up their diagnostic capacity. But although they’re cheaper, they’re considerably less sensitive than PCRs. Therefore, a negative result on a rapid test doesn’t roll out infection, and this is especially true for antibody tests: since antibodies take some time to form in the body, they might not be detectable for the first 10-14 days since infection. This is why the World Health Organization doesn’t recommend them for case detection.

Furthermore, the Antwerp Institute of Tropical Medicine, a leading institution in public health planning, says that although some have received approval to be used in the European Union, this is mostly based on information provided by manufacturers, and there’s little independent data to validate their use.

A good example of this is the recent decision of the United Kingdom to not use millions of recently bought tests that were found to be insufficiently accurate by Oxford University. Among the providers of these tests is Wondfo, a Chinese company whose antibody tests count with EU-approval and have also been bought by many other countries, including Venezuela.

This doesn’t mean these tests are useless. They’re recommended for research and to detect the presence of antibodies (which may confer immunity) in recovered patients. They’re also very good to retrospectively evaluate the exposure of a certain population to the virus, they just shouldn’t be used to diagnose new cases, at least not on their own. Even some high-income countries like Spain have incorporated rapid tests into their diagnostic algorithms, but negatives are retested with a PCR.

The Venezuelan government might not be lying at all here. It’s perfectly possible they have run 200,000 rapid tests, because they can be performed everywhere and they can give you a result in 15 minutes. It’s even possible (although unlikely) that only 227 of those tests were positive and were confirmed in Caracas. 

But if they’re relying solely on this strategy, and not confirming cases with PCRs, it’s also safe to assume COVID-19 is severely underdiagnosed in Venezuela.

Juan Carlos Gabaldón

Medical doctor from Merida, currently studying Medical Parasitology at the London School of Hygiene and Tropical Medicine