This is a summary, written by members of the CITF Secretariat, of:

Ings DP, Hatfield KM, Fifield KE, Harnum DOA, Holder KA, Russell RS, Grant MD. Few SARS-CoV-2 infections detected in Newfoundland and Labrador in the absence of Public Health Laboratory-based confirmation. PloS One. 2022 Jan 28;17(1):e0262957. Doi: 10.1371/journal.pone.0262957.

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

A study published in PLOS ONE by CITF-funded researcher Dr. Michael D. Grant, of Memorial University of Newfoundland, concludes that antibody testing is required in order to establish an accurate count of confirmed COVID-19 cases in the community. While PCR testing remains the most accurate method to detect active SARS-CoV-2 infection, it measures the presence of virus in the body, whereas an antibody test will determine whether a person was ever infected, either symptomatically or asymptomatically. Since most asymptomatic people won’t bother to get PCR tested, antibody testing is an effective method for getting an accurate measure of COVID-19 exposure rates. The research shows that, in the absence of confirmatory PCR tests, antibody testing successfully identified the immune status of persons suspected of having contracted COVID-19.

Researchers recruited volunteers who either recovered from a confirmed case of COVID-19 or believed they had been exposed to COVID-19, to study immune responses against SARS-CoV-2. They inquired if these individuals had been tested by a COVID-19 RT-PCR using a questionnaire. Their work showed that, in the absence of confirmatory PCR testing, antibody testing could identify whether individuals had, indeed, been infected.

Key points:

  • Most (~88%) COVID-19 PCR positive individuals showed the presence of antibodies against the SARS-CoV-2 spike receptor-binding domain (RBD) or full-length spike protein.
  • In some cases where individuals reported COVID-19 symptoms due to an exposure to a known COVID-19 case (while traveling or due to close contact with a confirmed case) but were not tested because of mild symptoms or regulations around PCR testing, these antibodies were also
  • Among PCR and seronegative individuals suspected of having COVID-19, the most frequently reported symptoms were primarily those often found in respiratory infections (cough, fever, fatigue, and shortness of breath most prevalent), together with headache, muscle aches and pains, sore throat, congestion and runny nose, nausea, vomiting, and diarrhea.
  • Many individuals in this group also reported their symptoms were more severe and longer-lasting than the flu or other common infections.

In summary, this study suggests that serosurveillance A process of serology testing, which is a test performed on blood to detect the presence of antibodies is an important ancillary techniques to identify the extent of population exposure to COVID-19.