Very early results from NC coronavirus antibody study are in. Here’s what they show

Wake Forest Baptist Health has released early results from fewer than 700 people in North Carolina’s first public study of coronavirus antibodies.

As of Friday, 1,475 antibody test kits have been sent to participants and results have come back for 676 of them, according to results posted by Sen. Phil Berger and the study’s lead researcher, Dr. John Sanders of Wake Forest.

Wake Forest Baptist Health invited 100,000 of its patients to participate in the study, which also includes surveillance for COVID-like symptoms. The vast majority of participants of the overall study are in the Triad region, according to maps provided by Wake Forest. Some live in southwestern Virginia. Wake Forest is working with Atrium, which will also begin picking some participants.

The initial enrollment of 7,194 people in the overall study has skewed toward white women. The subset of participants for the antibody testing will be selected to be representative of their counties of residence, according to Berger’s post. Atrium is working “to explicitly target recruitment of underrepresented populations.”

Antibodies for the coronavirus are present in 2.2% of the 676 participants with results so far.

“This figure (2.2%) is preliminary and should not be fully extrapolated to the broader population at this time, but certainly suggests a low seroprevalence in the Triad region,” Berger’s post said. Seroprevalence refers to how much of the population has been infected.

In the post, Berger said all of the content came from and had been reviewed and approved by Sanders.

The study hopes to reach 500,000 participants, though not all will be involved in the antibody portion. People are reporting daily if they have COVID-like symptoms.

There have been 33,304 daily symptom logs, according to a website created by Wake Forest Baptist.

Immunity?

It is expected that the presence of antibodies provide some level of immunity to the disease, as they do with other viruses. It is not known for how long any immunity would last.

“The durability of that protection varies depending on the virus,” Stephen Goldstein, a University of Utah virologist, told StatNews.

A new study indicates that everyone who had the virus is developing antibodies, not just those who developed significant symptoms, The New York Times reported.

“Studies are underway to address questions that will better inform the appropriate use of these tests, such as whether the presence of antibodies conveys a level of immunity that would prevent or minimize the severity of re-infection as well as the duration for which immunity lasts,” the Food and Drug Administration wrote on its website.

Herd immunity, or the percentage of the population that needs to be immune to keep a contagious disease under control, is between 70% and 90%, according to Johns Hopkins School of Public Health.

Test validity

The majority of the antibody tests are from Scanwell, which delivers a result at home. The rest are Neoteryx, which must be sent to a lab for testing. Berger said the tests have “undergone extensive validity” testing in partnership with LabCorp and the current validation tests show a specificity of greater of 99%.

Specificity is a measure of whether researchers are avoiding false positive results, which is important because false positives could lead people to believe wrongly they are protected.

The FDA has posted performance metrics for 12 serology tests authorized through Emergency Use Authorizations. Neither test used is listed among the 12. Scanwell is currently seeking an EUA for its test, according to GoodRx.

The FDA tightened its policy for antibody tests this week, in part due to companies making false claims about their tests and accuracy, The Los Angeles Times reported.

North Carolina has a statewide surveillance system for COVID-like symptoms. It relies on those visiting emergency rooms or clinics. Most recently, in the week ending May 2, less than 3% of emergency visits logged in the system were for those symptoms. Berger wrote that the Wake Forest study has found “surveillance daily symptom reports show an extremely small current prevalence of COVID-like symptoms.”

The surveillance is one of the seven benchmarks that Gov. Roy Cooper has laid out for moving the state’s re-opening to new phases. North Carolina entered Phase One on Friday at 5 p.m.

The state has completed more than 178,000 tests for the active virus — different from antibody testing. There have been more than 13,800 laboratory-confirmed cases of COVID-19 in the state and more than 520 people have died, according to data released Friday by the state.

Legislature pushes for antibody testing

Republicans in the North Carolina General Assembly, led by Berger, have pushed for antibody testing since early in the outbreak.

“Nobody knows the true hospitalization and fatality rates for this virus, even as the government has ordered a full-scale economic shutdown,” Berger said in April at a time when the state had fewer than 5,000 cases and about 100 deaths.

The legislature provided $100,000 from its own budget to the study to help get it launched. More recently, state lawmakers allocated $20 million to Wake Forest University Health Series as part of a spending package of $1.6 billion in federal aid for dealing with the coronavirus pandemic.

This story was originally published May 8, 2020 at 7:38 PM.