A REVIEW BY Ireland’s health watchdog has found mass thermal screening at airports is ineffective in limiting the spread of Covid-19.

The Health Information and Quality Authority (Hiqa) today published two summaries on the best available evidence on the use of thermal screening to effectively identify cases of the disease in passengers.

Mass screening programmes using non-contact devices like infrared thermal scanners were not found to be effective in identifying infectious individuals and limiting spread of disease. Hiqa said detection rates were consistently low across studies.

Dr Máirín Ryan, Hiqa’s deputy CEO and director of health technology assessment, said thermal screening has been used in other respiratory infectious disease outbreaks, such as the 2009 H1N1 influenza pandemic in Asia and Australia, to improve detection and reduce the time to isolation of infected individuals.

“It typically involves a combination of fever screening, such as temperature testing, alongside self-reporting of exposure risk and or symptoms,” she explained.

“However, the evidence clearly shows that this type of test is likely to be ineffective in limiting the spread of Covid-19. Thermal screening is noted to be high cost and resource intensive. Detection rates are very low due to a large proportion of cases that have no symptoms, are infectious before showing any symptoms or who do not present with fever.”

Hiqa identified 11 primary studies, three rapid reviews and one systematic review relating to Covid-19 and other respiratory virus pandemics. All studies were conducted in the context of points of entry such as airports, so the watchdog said their relevance to other community settings such as schools is uncertain.

The authority has also updated its evidence summary on the immune response and potential immunity following infection with Covid-19 and other human coronaviruses.

Dr Ryan said it remains unclear whether long-term immunity to SARS-CoV-2 – the virus that causes the Covid-19 disease – is possible.

“SARS-CoV-2-specific IgG (immunoglobulin G) antibody was detected in nearly all individuals up to three months after they were infected, and over 90% of patients had developed a neutralising antibody response, which protects against viral infectivity,” she said.

“However, a handful of new studies suggest that it may be possible to be re-infected with SARS-CoV-2. HIQA will continue to monitor the evidence on immunity and update our summary as required.”