Pennsylvania State Representative Brian Sims, a Democrat, posted an explosive Twitter thread Wednesday evening warning that he may have been exposed to the coronavirus by his fellow Republicans – and that those colleagues have kept him in the dark .

Shortly before the Sims tweets, a Republican representative, Andrew Lewis, released a statement admitting that he “was tested for COVID-19 and on Wednesday, May 20, I was notified that my test came back positive. Lewis said he isolated himself and “contacted the House of Representatives and our caucus human resources department.” Lewis also claims he worked to determine “exactly who I was with may have been in contact and with whom I may have been exposed to the virus “.

The Pennsylvania House of Representatives held in-person sessions while Democrats say they were unaware of Lewis’s diagnosis.

And yet, while Lewis tested positive on May 20, Democrats say they only learned that one of their colleagues could have exposed them to the virus before Wednesday May 27. According to Representative Dan Frankel, the top Democrat on the House Health Committee, members of the Democratic caucus learned on Wednesday “that four members of the Republican caucus have been quarantined after one of those four tested positive for COVID-19 a week ago. “

One of those four members, Republican Russ Diamond, posted a long statement on Facebook Wednesday night attacking the very idea that public health officials should engage in contact tracing to determine who may have been exposed to the virus.

Diamond says he made the decision to self-isolate “because I wanted to give an example of how responsible adults can lead their lives without needing harsh government mandates,” before claiming the real problem is that someone might be wrongly advised to quarantine:

There are many things to object to about contact tracing of this type. I was not offered any evidence that the person I was “in contact” with had previously contracted, and was an asymptomatic carrier, of COVID-19 on May 14. What if this notice was sent to me in error? I happen to know someone else who received a similar notice by mistake. This person was fortunate enough to be able to clarify and correct the file and to avoid self-quarantine. However, if a government agency with enforcement power sent these notices, would it be able to obtain such a correction? I highly doubt it.

As the Washington Post notes, Diamond is a “vocal opponent of wearing masks. “The same day Diamond began his self-quarantine, he spoke to a panel at Pennsylvania House without wearing a mask.

Yet despite his demeanor, Diamond is right about one thing. Contact tracing is not a perfect system. Contact tracers are a kind of public health detective; they interview people diagnosed with the virus and try to find out who they may have been exposed to the disease. But respiratory viruses such as the novel coronavirus are difficult to track because many people infected with the virus will not remember everyone they may have come into contact with, and they might not even be aware of people who are infected with the virus. could have entered a room shortly after the infected person left.

This is why Republicans should have informed their Democratic counterparts about Lewis’ infection. Even though Lewis and his fellow Republicans have made all reasonable efforts to find out who Lewis may have been exposed to the virus, such efforts are not 100% reliable. And if Lewis unknowingly infected someone before self-isolating, that person could also spread the disease throughout the state legislature and beyond.