SAN JOSE, Calif. (KRON) – As more people are getting vaccinated against COVID-19, fewer are getting tested.

That is making it harder for public health to track the spread of the virus.

Back in January, there were long lines here at this drive-thru test site at the county fairgrounds.  

On Monday, there was no wait at all. That’s worrisome because testing is the best way to learn about the spread of infection but also to discover if there are any new and more contagious variants in the community.  

Reflecting a national trend, rates of COVID-19 testing are down across California since January.  

Tests at this and other sites across Santa Clara County have fallen 30-percent. 

Much of the decline is thought to be the result of less fear of exposure as more people are vaccinated.  

Public health is troubled by the trend — It is at test sites where new and potentially more contagious strains or variants of the virus are detected.  

Fewer tests narrow the view of where the infection is circulating and make it easier for the virus to spread and mutate into one of those troublesome variants, says the county’s testing officer, Dr. Marty Fenstershieb.

Testing is crucial because it can also help identify the rare instance where a vaccine does not guard against infection.  

Chris, who has one dose of vaccine onboard, is getting tested on a regular basis just to be on the safe side.

Testing can help gather information for the development of vaccines that might be more effective against emerging variants. Get tested even if you’ve been fully vaccinated, says Dr. Fenstersheib.