Test for Covid sooner after contact, experts advise

It can be very helpful in the fight against the spread of the coronavirus to test people three days after they had contact with someone who has Covid-19, instead of waiting five days as the RIVM guideline states, Amrish Baidjoe, field epidemiologist and member of the RedTeam, said to BNR.

"There are two reasons why the Delta variant [of the coronavirus] is spreading faster: a shorter incubation period, which is more in the direction of three and a half to four days, and that people infected with the Delta variant seem to produce a thousand times more virus," Baidjoe said. "What we hope to break with earlier tests is the chain of transmission. The sooner you detect an infected person, the sooner someone can be isolated and infect as few others as possible."

Public health institute RIVM is hesitant to shorten the waiting time between Covid-19 contact and testing. According to Baidjoe, this is likely because the original variant is still around and that can only be detected after five days. "Nevertheless, the Delta variant is well on its way to taking over the entire spectrum. People could get tested more often, which is common in a country like Norway, where they also test after three days, but where you still have to stay in quarantine until you get tested after five."

Molecular virologist Marjolein Kikkert of LUMC in Leiden agrees that testing earlier could make sense, but she also noted that this could result in the original variant being missed. "A number of infections are still with older variants and they are a bit slower. If you start testing after three days, you could still miss it, you can still develop it if you had that old variant and you have to test again after five days to be sure. Four days of testing seems like a good idea to me."

She added that the RIVM guidelines state that after you had contact with someone with Covid-19, you should quarantine and isolate yourself until after you got tested five days later. If people adhere to this measure, the need for earlier testing would disappear.

Public health institute RIVM told BNR that it has no plans to amend the current guideline, but it is keeping a close eye on what scientists conclude with regard to the Delta variant. There is currently no scientific consensus on this, the RIVM said.