No evidence children are Covid-19 ‘super spreaders’, says Hiqa

Analysis of global research likely to inform NPHET decisions on when schools reopen

Children are not substantially contributing to the spread of Covid-19 in their households or in schools, according to the Health Information and Quality Authority (Hiqa).

Its findings in analysis of latest global research are likely to inform the National Public Health Emergency Team's position on re-opening schools, particularly at primary level.

At the early stage of the pandemic there were fears that children were vectors in transmitting the disease, but Hiqa deputy chief executive and director of health technology assessment, Dr Máirín Ryan said there was nothing to indicate children transmit the virus at a substantially higher level compared to other age categories.

In its latest evaluations of research to assist NPHET’s response to Covid-19, Hiqa also conclude there is lack of clear evidence as to whether long-term immunity is possible with Covid-19.


On the issue of young people, Dr Ryan said: “While the evidence is limited, it appears that children are not substantially contributing to the spread of Covid-19 in their household or in schools.”

While there is high transmission of Covid-19 among adults aged 25 years or older, she pointed out one study which showed transmission is lower in younger people particularly in those under 14 years of age.

An Australian study that examined potential spread from 18 confirmed (nine students and nine staff) cases to over 800 close contacts in 15 different schools found that no teacher or staff member contracted Covid-19 from any of the initial school cases.

There remains a lack of clear evidence as to whether long-term immunity is possible from SARS-CoV-2 the virus that causes Covid-19, the Hiqa investigation concludes.

Dr Ryan added: “Studies have shown that antibodies against SARS-CoV-2 develop soon after infection. Immunoglobulin G antibodies (that contribute to long-term immunity) have been detected for at least two months after infection.”

However, as SARS-CoV-2 is a new virus, there is no long term evidence of immunity, she underlined, while continued monitoring was needed to assess the adequacy and duration of the immune response for Covid-19.

Evidence for other types of serious coronavirus infections, such as SARS-CoV-1 – known as SARS – shows the antibody response is maintained for one to two years after initial infection and decreases thereafter.

“As yet, it is also not certain if antibodies are transferred from mother to the child in the womb via the placenta,” Dr Ryan said.

It is not yet possible to determine if reinfection is possible following recovery from Covid-19, Hiqa conclude in its review of the evidence.

“While some individuals have tested positive after recovery, this is likely due to virus re-detection where there is intermittent shedding of the virus rather than reinfection with a second virus. To date, there is no evidence that these individuals are infectious to others.”

Dr Ryan said hundreds of antibody tests which have been developed are being evaluated for validation purposes to confirm their accuracy. This was being overseen by WHO and the European Commission. Quality assurance was also needed if they were to be deployed in Ireland.

A range of new faster tests to confirm infection were also going through validation. The first results on these related to lab tests, while the next stage would relate to swab tests.

Evidence summaries are developed by Hiqa following requests from NPHET's Clinical Expert Advisory Group and inform the national response to the pandemic.

Hiqa develops “evidence summaries” following a thorough search of databases, screening of identified studies to match relevant clinical questions, data extraction and quality appraisal of related studies. “This robust process ensures public health decisions are informed by the best available evidence and information from across the world,” Dr Ryan noted.

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times