Even before the coronavirus pandemic, robocalls remained public enemy number one for the FCC and pretty much anyone with a phone. Now, they’re interfering with a key coronavirus defense strategy — contact tracing.

Robocallers have gotten good at using fake caller ID and other clever tactics to bypass call filtering and number blocking to get you to pick up — which has, in turn, left some people to simply stop answering their phones when a call comes from a number they don’t know.

According to Transaction Network Services, a company known as TNS that provides telecom data and call filtering for companies like Verizon (Yahoo's parent company), Sprint, US Cellular, and more, the 86 million robocalls have Americans receive every year has been disrupting the contact tracing efforts, rendering them less effective.

TNS said that recent research found that 83 out of 100 residents who received a COVID-19-related contact tracing call thought it was a scam.

TNS has identified 8.2 million contact tracing calls since May. While it doesn’t have specific answer rates for those calls, its data shows that only 8%-10% of the population answer a call when only a number is listed on the caller ID. When there’s more caller ID information, the answer rates go up to around 40%.

This is thanks to robocalls, that have killed the credibility of a call from an unknown number.

“We'd venture to say that agencies around the country don't realize how big this problem is nor are leveraging a service provider to get their contact tracing calls answered,” TNS’s chief product officer Bill Versen told Yahoo Finance.

The tough thing here is that sometimes it actually is a scam. According to the FTC, contact tracing has been a gambit for scammers during the pandemic, leading the agency to advise people that contact tracers will never ask for Social Security numbers, immigration status, bank account or credit card details, or ask you to click on any links or download files.

Contact tracing requires you to answer the phone if the health department calls

Contact tracing — getting in touch with people who have come in contact with the virus — in some countries has worked well using both phone calls and apps. But privacy concerns around data as well as the low credibility of unsolicited calls poses a problem for efforts in the U.S. (Though Versen added that Canada has a similar problem with spam calls.)

Some contract tracing operations have recognized this problem and have taken TNS up on its free caller ID services, which allow tracers to boost their answer rates.