An illustration showing how a sample is collected for a PCR test to see if a patient is currently infected with Covid-19 (click image to enlarge). Source: New England Journal of Medicine (no copyright infringement is intended).
Some residents are getting tested for the antibodies to the Covid-19 virus to see if they’ve already been infected, but some of them get an unpleasant surprise: mandatory isolation if the result is positive, even if they feel fine.
Tricia McGean, Lincoln’s public health nurse, gets the result whenever a Lincoln resident is tested either for a current infection, or for antibodies indicating that they were infected earlier. The infection test uses a nasal swab and is sometimes referred to as a PCR (polymerase chain reaction) test.
Serological blood tests for Covid-19 antibodies have recently become available, and some people have taken that test to see if they’d already had the infection, with or without symptoms. “A couple of people told me they did it for fun,” she said.
However, new guidelines handed down late last week by the Massachusetts Department of Public Health require people who test positive for Covid-19 antibodies to immediately self-isolate (even from family members) for at least 10 days — unless they previously had a positive PCR test. For those who never had a PCR test, they can get that test after their antibody test. If that PCR result is then negative, they don’t need to continue isolating — but until the test result comes back, they must isolate. This is because, depending on the types of Covid-19 antibodies they have, they actually might be recovering from a recent infection (even without symptoms) and could still spread the virus.
As soon as McGean learns of a positive antibody result by a Lincoln resident, she’s required to contact the person and order them to isolate. She must also interview them about close contacts and quarantine those close contacts for 14 days.
“This is not going over very well, as you can imagine,” she said at her weekly Covid-19 update to the Board of Selectmen this week. “We weren’t expecting this. They change guidances quite frequently, so hopefully this won’t be the end guidance.”
Relatively few people who weren’t feeling sick got PCR testing until recently because the test was hard to obtain earlier during the pandemic, but they’re more accessible now, McGean added.
This summary sheet explains the required public heath responses to test result scenarios. It acknowledges that the guidelines are conservative due to uncertainty about the quality of the various antibody test types as well as the unknown timing of Covid antibody development or duration. “This guidance will change as we learn more about antibody responses to Covid,” the sheet says.
Here’s a brief Q&A with McGean about timing for those who are thinking about getting a Covid-19 antibody test:
Q. How does my antibody test result get conveyed to the town’s public health nurse?
A. Just like Covid-19 infection results, this happens through the state’s MAVEN website. A majority of my day is spent on this website, so once it’s uploaded, I usually see it quite quickly.
Q. How quickly can I get a PCR test, and where?
A. That’s the million-dollar question, but there are many resources online where you can go for testing. I don’t do them myself.
Q. How soon after I have the PCR test will we receive the result?
A. Usually fairly quickly. It depends if the lab calls the patient or the doctor who ordered it or me when the result comes into MAVEN.
Q. Do I have to self-isolate while I wait?
A. Yes. If your antibody test is positive [and you didn’t have a positive PCR test result before that], you have to be in isolation until we get the PCR test back. The turnaround time for PCR testing has been much quicker recently, with often a 24- to 48-hour turnaround time.
