REUTERS

COVID-19 is many times more prevalent in Indonesia than shown by official figures in the world's fourth most populous country, authors of two new studies told Reuters.

The country of 270 million has recorded 1.83 million positive cases, but epidemiologists have long believed the true scale of the spread has been obscured by a lack of testing and contact tracing.

The results of Indonesia's first major seroprevalence studies - which test for antibodies - were revealed exclusively to Reuters.

One nationwide study between December and January suggested 15% of Indonesians had already contracted COVID-19 - when official figures at the end of January had recorded infections among only around 0.4% of people.

Even now, Indonesia's total positive infections are only around 0.7% of the population.

The results of the survey were not unexpected given under reporting, said Pandu Riono, a University of Indonesia epidemiologist who worked on the study carried out with help from the World Health Organisation.

Siti Nadia Tarmizi, a senior health ministry official, said it was possible the study was preliminary, but there might be more cases than officially reported because many cases were asymptomatic.

She said indonesia had low contact tracing and a lack of laboratories to process tests.

Based on blood tests, seroprevalence studies detect antibodies which show up people who likely already contracted the disease. The official figures are largely based on swab tests, which detect the virus itself and only reveal those who have it at the time.

Antibodies develop one to three weeks after someone contracts the virus and stay in the body for months.