The World Health Organization has approved a new rapid antigen test (Ag RDTs) for use by low and middle-income countries. The test gives results in just 15 minutes. Importantly, it comes cheap. Each test costs just under USD 5.

The benefits of Ag RDTs are many. "The test works best when an individual has a high viral load and likely to be in the more contagious phase of infection. Need to ramp this up so everyone can be tested regularly," says an expert. Epidemiologist Maria Van Kerkhove adds, "Ag RDTs perform best in areas of active transmission and when collected from a case when they have their highest viral loads: approximately 2 days before and up to 5-7 days after symptom onset."

The WHO has earmarked a budget of $600 million for the scheme.

As many as 133 countries will benefit from the scheme over the next six months.

Are they better than the RTPCR tests? The answer is a big no. However, they are faster, cheaper and easier to carry out, reports say.