Promega is in the early research phases of evaluating COVID-19 immune response tests.

As the novel coronavirus has made its way around the planet, so too has the effort to understand how the disease spreads and who develops immunity to it.

Companies both here at home and globally are racing to achieve that understanding.

One of those is Promega, which is in the early research phases of evaluating COVID-19 immune response tests, senior communications specialist Karen Burkhartzmeyer told the Star.

As part of that evaluation, the Fitchburg biotech business is seeking participants who have previously contracted SARS-CoV-2, the virus that causes COVID-19, to be involved in an antibody study. Promega staff will test each participant for disease antibodies using tube samples of their blood — a test known as a serological assay.

Promega’s chief medical officer, Ashley Anderson, wrote in an April 8 blog post that such testing, already carried out by laboratories around the country and world, suggests there might be far more people who have had the disease than previously thought.

That could have profound implications for how governments and businesses will continue to respond to COVID-19 in the coming months.

“The need for reliable virus detection methods is central to the global response to COVID-19,” Anderson wrote. “The test results not only inform health decisions for individual patients, but they also help us build projections of how the virus will spread, which can in turn influence policy decisions.”

While that’s possible, he said there is much to be learned about how long people remain immune to COVID-19.

“Widespread deployment of this type of test would help us predict whether the infection rate will increase or decrease in a given area, baked on the percentage of the population that is immune to the virus,” he wrote.

Decoding the science

Anderson wrote that serological assays provide promising research tools amid an uncertain health crisis.

He said they can address what diagnostic, or Polymerase Chain Reaction-based, tests haven’t – finding out which patients contracted and recovered from COVID-19 based on the presence of antibodies in their blood.

“PCR-based tests were developed and deployed to detect the virus in patients in hospitals,” Anderson wrote. “Those tests have been crucial to monitoring infection rates and informing patient treatment, but at this point they have fallen short of providing an overall picture of the pandemic.”

That’s because thousands of individuals have gone untested because they either have mild to undetectable symptoms or they simply don’t have access, he said.

“Since PCR-based methods can only tell us if the virus is active in the patient at the time of the sample, and offer no information about whether a patient was (previously) infected, we currently have no way to determine how many of these unconfirmed cases exist, or which patients have recovered,” Anderson wrote.

She said viruses like SARS-CoV-2 carry a special spike protein allowing them to enter host cells. To attack the infection, the body’s immune system produces antibodies that bind to the protein and activate other immune cells to destroy the virus.

These antibodies remain even after the infection is gone, and exactly how long they remain is still being studied.

“If a serological assay detects the antibodies specific to a given virus, we can conclude that the patient has been infected in the past,” he wrote.

More widespread than thought

Serological assays have seemed to suggest thus far that more people are contracting COVID-19 then previously thought — their symptoms are so mild they are almost undetectable, if at all.

For example, a study by both the University of Southern California and Los Angeles County Department of Public Health showed the actual number of infections in the county may be as high as 55 times the current number of confirmed positive cases in the area.

After administering antibody tests to 900 people, researchers estimate as many as 442,000 people throughout the county – out of a population of around 8 million – had the virus as of April 9, ABC News reported on April 20.

If more research suggests the above, that means the disease is likely less lethal than current case fatality rates predict — with around 3 million confirmed cases worldwide and 200,000 deaths, that would roughly come out to 6%.

But whatever the outcome, Anderson said continued collaboration among scientists and researchers is key to solving the COVID-19 health crisis.

“We are in this fight together,” he wrote.

Email Emilie Heidemann at or follow her on Twitter at @HeidemannEmilie.