The World Health Organization (WHO) recommends 10 – 30 tests per confirmed case. However, there is no consensus among experts on the recommended target number of tests.
World Health Organization
- The World Health Organization (WHO) recommends “10 – 30 tests per confirmed case as a general benchmark of adequate testing.”
- The WHO recommends a 10% test positivity rate. According to Michael Ryan, executive director of the Health Emergencies Program at the World Health Organization, “if 80-90% of the people test positive,” it means that a lot of cases are being missed.
- This is because, “the more positives means the tests are being used mainly to confirm obvious cases, and as a result, health authorities are not getting a clear picture on the scope of the epidemic in their area.”
Harvard Global Health Institute
- The Harvard Global Health Institute in collaboration with TTSI Collaborative members came up with key metrics that can be used to “evaluate the status of COVID response and key performance indicators to evaluate how well particular tools of response are being deployed.”
- According to the New York Times, “Harvard researchers say that at minimum there should be enough daily capacity to test anyone who has flu-like symptoms and an additional 10 people for any symptomatic person who tests positive for the virus.” This level of testing is the minimum required to mitigate the virus.
- The TTSI Key Performance Indicators recommend a less than 3% positivity rate for tests required to suppress the virus.
Positivity Rates and Tests Per Capita
- According to Johns Hopkins Coronavirus Resource Center, there is no consensus among experts on the recommended target number of tests or even the per capita testing rate. However, they recommend using the positivity rate to determine if testing is enough.
- According to Johns Hopkins Coronavirus Resource Center, it is important for governments to scale their testing programs according to “the size of their epidemic, not the size of the population.”
- Countries such as Iceland, South Korea, and Norway have been identified as case studies on how COVID-19 testing contributes to flattening “of the epidemic curve of new infections with a relatively low number of deaths.”
- Iceland has an average daily testing rate of 221 per 100, 000 population, South Korea has an average daily testing rate of 79 per 100, 000 population while Norway has an average daily testing rate of 275 per 100, 000 population.
- According to the Johns Hopkins Coronavirus Resource Center, the latest number of daily total tests in California is 218,152. The latest available number of daily new cases is 16,696.
- According to data from Covid ActNow, California’s new cases per 100,000 residents was 346.2 in the last seven days. The positive test rate was 12.8%. The positive test rate is higher than that recommended by the WHO and Harvard researchers.
- According to Covid ActNow, this “indicates that testing in California is limited and that most cases may go undetected.”
- According to the TTSI Key Performance Indicators, for California to suppress the COVID-19 virus, the number of tests per 100,000 residents should be 33 times the number of daily new cases.
- Estimated daily tests needed = 33 X daily new cases = 33 X 16,696 = 550,968 tests (5.5 tests per 100,000 residents).