< Back News

Public Health Gibraltar Statement on Discrepancy in Test Results on Footballers – 585/2020

By September 1, 2020 No Comments

GHA Public Health University Lab (PHUL) results returned negative on the screening tests performed on the same working day on all players. Public Health Gibraltar understands results from Kosovo on all players before they left for Gibraltar and on return were also negative.

As part of internal quality assurance Public Health Gibraltar undertook to undertake further tests by a different, diagnostic test method used in the St Bernard’s laboratory, on the samples available in Gibraltar on all 15 footballers who had tested positive. Of these only 1 tested positive at a very low level and another equivocal by this alternative method: according to diagnostic protocols, both would have required further confirmatory testing before a definitive result could be issued. All remaining 13 footballers tested negative by an alternative method.

Whilst there are a number of possible scientific explanations for this, conclusions from the available data suggests that, in the event the Kosovan footballers were genuinely positive for COVID RNA, this was at a very low level, a level at or below the limit of detection for local tests. This level of viral RNA was a) at a level considered below the threshold set for local screening tests, which aim to detect those without symptoms but with high levels of virus (i.e. those that pose the biggest risk for transmitting infection in our community) with a very high level of accuracy and b) at level considered not to signify with infectiousness (or presence of infectious, viable virus) in the subject. Very low level positives can be caused by viral RNA fragments which can persist for weeks after infection or from external sources, including environmental contamination. Additionally, the difference in sample type for Synlab: a deep nasal (nasopharyngeal) swab versus that for PHUL: a throat swab may have contributed. Differences between swabbing approaches may be more marked where there is a low level of viral RNA present as opposed to those with high levels of viral RNA where virus is present throughout. Finally, there is the impact of test specificity. The LAMP test used for screening in the GHA PHUL carries an extremely high level of specificity through use of sealed reaction tubes and a secondary analytical step that confirms any RNA detected is that of COVID. Furthermore, all positives detected in the GHA, be it PHUL or St Bernard’s Laboratory are sent to the UK for whole genome sequencing to confirm the RNA is that of SARS-CoV-2 that causes COVID.

The COVID tests undertaken in Gibraltar for diagnosis and screening vary, having been selected with careful consideration. In particular, our population-based screening LAMP test has been selected on the basis of excellent performance in detecting those with higher levels of virus who are most infectious, rapid test turnaround time and extremely high specificity to ensure positives are true positives- allowing for rapid public health intervention. Such LAMP tests are in use for population based screening in the UK and being piloted more widely at national level. It is the view of the relevant professionals in Public Health Gibraltar that using different ultra-sensitive tests for screening those without symptoms runs the risk of generating significant numbers of false positives or positives from those with recovered infection which would lead to unnecessary and inappropriate quarantine & isolation for large numbers of individuals and their contacts, with consequent negative impact on individuals, services (including education & healthcare), businesses and the community.