The Health Services Authority plans to commence antibody testing this week.
The HSA, in a statement Wednesday, said the antibody testing will prioritise healthcare workers and individuals who have previously tested positive for COVID-19, before a public-screening programme planned by Public Health gets under way.
The Immunoglobulin G, or IgG, antibody testing will help better understand the effects of COVID-19 in the Cayman Islands, according to a statement release by the HSA.
The antibody test can detect IgG responses in the blood, indicating that the body has mounted an immune attack against the SARS-CoV-2 virus. The presence of these antibodies can also indicate if a person has previously been infected with COVID-19.
“While the PCR (polymerase chain reaction) method is currently the most accurate test available for active COVID-19 disease, the test does not identify whether someone has previously been infected with the virus. To answer this, the HSA will begin rolling out antibody testing this week as part of Public Health monitoring,” said Dr. Delroy Jefferson, medical director at the HSA.
Dr. Samuel Williams-Rodriguez, medical officer for health, said the antibody testing will be rolled out to the wider public in a similar manner as the PCR screening programme.
“Testing will be conducted across sample sized groups that will be nationally representative and give us a good indication on the level of infection in our community. The HSA will contact these sample groups for testing over the coming weeks,” he said.
Williams-Rodriguez said the availability of antibody testing allows Cayman to double its COVID-19 screening efforts.
“[It] gives us a holistic view of the impact of COVID-19 in our community. Both PCR and antibody testing provide different functions in relation to COVID-19 so being able to use both tests simultaneously greatly enhances our efforts,” he said.
“However, it is important to note that the presence of SARS-CoV-2 antibody does not necessarily mean that you are immune to COVID-19, and normal precautions to protect yourself from the virus should remain in place.”
The tests detect antibodies in the blood caused by an immune response to SARS-CoV-2 virus. Antibodies start to develop in most patients 7-10 days after symptoms of COVID-19 begin and remain in the blood after the infection has passed.
In antibody testing, blood is drawn and sent to the lab, and a result is provided in 24-48 hours.
Faster PCR test results
Cayman recently acquired a GeneXpert machine, which the HSA said will allow a “faster turnaround time” for the PCR testing of clinically urgent cases, with results being available in 45 minutes.
PCR tests are typically done via nasal swab in Cayman.
“The introduction of the new GeneXpert machine will allow us to keep medically urgent tests separate from routine screening samples. The quick turnaround time is also vital for patients needing emergency treatment or emergency transfer abroad,” Jefferson said.
The HSA forensic lab was the first among the Overseas Territories to introduce PCR testing in March to detect the presence of COVID-19.
The GeneXpert machine and associated PCR cartridges were donated by the UK government through the Foreign and Commonwealth Office, following organisation by Public Health England.