(KRON) — Examining wastewater is now giving infectious disease experts a clearer picture of how bad this current COVID-19 surge is.

“The wastewater is telling us that it’s still at a very high sustained concentration, which means is actively circulating in the community, and people should continue to take precautions to protect themselves from transmission of the virus,” said Michael Balliet, Santa Clara County Public Health Department.

The surge in Santa Clara County and other parts of the state is approaching levels seen during the surge last winter, with one worrisome difference — it’s lasting longer.

KRON On is streaming news live now

“The width of this surge is broader than the width of the December January surge. So at the end of the day, we’re going to have more people who got infected during the surge, then possibly even in December or January, it’s a little early to call that exactly,” said Dr. George Rutherford, UCSF Epidemiology professor.

Dr. Rutherford said people can protect themselves by getting boosted, avoiding large crowds, and masking indoors.

“You don’t want to get this. It opens the doors for long COVID syndrome and a bunch of other stuff. And your prior infection is not going to protect you for that long. It looks increasingly like the BA.4 AND BA.5 for the naturally acquired immunity only lasts for maybe a month,” said Dr. Rutherford.

Experts also suggest not coming out of isolation too quickly after you are infected.

“People are shedding the virus much longer than five days. Not everybody certainly but a lot of people are some people out to 10 days, some people even more than 10 days,” said Dr. John Swartzberg, UC Berkeley Infectious Disease Specialist.

Dr. Swartzberg said even though the CDC says if you feel well after five days you can come out of isolation if you’re wearing a mask, he said that’s based on old data. He added a negative test is a safer way to go and will help keep the virus from spreading.

“The reason why I would add the rapid test on to that is because the rapid test is usually negative at the time when you’re not having much virus at least enough willing to spread. So if you are without symptoms, it’s been more than five days your rapid test is negative. I think the chances of spreading the virus are very low,” said Dr. Swartzberg.