Researchers at King’s College, London, have found that self-administered, at-home antibody testing could be a simple method for virus surveillance on university campuses.
*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
The coronavirus disease 2019 (COVID-19) pandemic has led to almost total lockdowns in many countries, resulting in severe disruption to normal life. Education has been greatly affected by extended school and college shutdowns.
Following the initial lockdown in March 2020, the United Kingdom (UK) has had a series of reopenings and further lockdowns to curb regional transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19.
This has affected the higher education sector, which has had to manage the risk of spreading the virus by staff and students traveling to and from campuses.
One method for understanding this risk is to identify people who have been previously infected with the virus, as this could help identify behaviors and characteristics associated with a high risk of infection, which can then be used to put prevention measures in place.
Previous SARS-CoV-2 infection is usually identified by testing for antibodies. Studies have shown 90 percent of patients develop specific IgG and IgM antibodies by 11 to 24 days after symptom onset. However, this test requires in-person testing, which can be difficult to carry out with COVID-19 curbs and social distancing measures.
To get around this, researchers from King’s College London tested the feasibility of home antibody testing. They reported their initial results in a paper published on the medRxiv* preprint server.
At-home antibody test feasibility
The study was performed as a part of the King’s College London Coronavirus Health and Experiences of Colleagues at King’s (KCL CHECK), which explores the psychological, physical and social impact of COVID-19 on postgraduate research students and staff members of King’s College.
Researchers asked study participants to complete a SureScreen Diagnostics COVID-19 Rapid Test Cassette, an immunoassay to detect IgG and IgM antibodies to the spike protein, in June (Phase I) and September 2020 (Phase II).
Participants uploaded their results onto the study website, which were then analyzed along with the sociodemographic information.
A total of 2,288 and 2,284 participated in the testing in Phase I and Phase II, respectively, resulting in a little more than 90 percent of valid tests. Approximately 6.5 percent of the tests were positive in Phase I and 5.4 percent in Phase II.
In Phases I and II, the positivity rate among staff was 6.4 percent and 5.1 percent, and among postgraduate students, it was 7.9 percent and 6.8 percent.
The positivity rates are similar to that across England during Phase I. However, the positivity rate decreased during Phase II, in contrast to that of the overall population.
Although the study shows that it is feasible to implement low-cost serological testing without the need for in-person contact in an occupational setting, the authors note some limitations.
The diagnostic kit was approved for testing venous blood and there is little data on how it performs on capillary blood. This could have introduced additional uncertainty in the results.
The team relied on the photographs of the results provided by the participants, and results had to be recorded within 10 minutes of adding the buffer solution. The guidance documents developed by the team to help participants carry out this step correctly appear to have been effective.
In summary, the authors write, “We found that it was possible to conduct mass testing of postgraduate research students and members of staff at King’s College London using serological cassette testing on two separate occasions.”
The team plans to continue antibody testing in order to document changes in antibodies and identify any correlations with changes in physical or mental health.
This will allow them to identify patterns that can help reduce disease spread, increasing the understanding of how antibody testing can be used in public health management.
*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
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