During filming of ‘Questions for Dr Brink’, she was asked a question by a health care worker about when they were likely to expect antibody testing to begin, stating they had been waiting two months.
Dr Brink said they needed to be careful with the use of antibody testing but that it could be available ‘over the next month’.
Although Public Health England yesterday gave the go-ahead to a Swiss pharmaceutical company-developed new blood test, known as the Roche’s serology test, after finding it was ‘highly specific’ with 100% accuracy in determining if a patient has had Covid-19 and whether they have developed antibodies against it, Dr Brink said the Bailiwick would be careful in its choice and what it would be used for.
‘You’ve got to ask, what are you testing for,’ she said.
‘I think there are a number of situations where I would envisage antibody testing coming in, [but] if you’re talking about testing staff to see if they’re immune, I would be very concerned about relying on the presence of antibodies to say a staff member was immune to the virus.
‘The antibodies that we test, we don’t know what type of antibody they’re measuring or indeed if they are what we call neutralising antibodies, so it would prevent someone from getting infected.
‘So if someone was antibody positive and was a staff member, we would still want them to take all the precautions, wear PPE [personal protection equipment] and so on.’
She added there would be specific clinical situations where antibody testing would be beneficial.
‘Antibody testing might be helpful in people who you think have had Covid and actually have got rid of the virus but still have some symptoms that you think could be Covid-related,’ she said.
‘So some of the symptoms in the latter part of the Covid infection can in fact be caused by the body’s immune system, so in those situations antibody testing may indeed be useful.’
Dr Brink also highlighted the problems with some antibody tests.
‘There are various tests being looked at and one of the lateral flow tests which are the cassette tests, the finger pricks, so a bit like a pregnancy test, and those have had some problems,’ she said.
‘They are being used but from our perspective we’d rather use the well-based assays, the 96-well-based assays.
‘We have purchased some of those and we’re looking at standardising those but our focus at the moment is on enhancing our direct viral detection but also alongside that developing antibody testing – I would envisage that that would be available over the next month.’
Their current preferred option, known as the 96-well-based assays, involves taking a blood sample which is then tested using multi-channel plates that can process 96 blood samples at a time.
Dr Brink said towards the end of the year they might look at what the islands’ rates of infection are in the population.
‘We expect they’re very low, so our seroprevalence [the level of a pathogen in a population, as measured in blood serum] in the population is going to be way under 5%, probably under 2%.
‘We think from our perspective doing a population-based seroprevalence survey would be too early, and indeed we need to focus our resources [where] we’re going to get the most population based benefit, which is why we’ve launched our Bailiwick Extended Testing Strategy which is focusing on the direct detection of the virus, and we want to rapidly increase the number of cases we test up to around 400 a day.
‘So we’ll be really ramping up our direct viral testing.’
