Covid is an airborne disease, predominantly transmitted person-to-person, and virologists have been advising since the alarm was first raised that indoor spaces where people mix should have the best possible ventilation. Transmission is further inhibited if people wear masks.
Last Tuesday on RTÉ’s Prime Time, Health Minister Stephen Donnelly struggled to explain why the Government has opted for open windows and masks in schools but has declined to provide or mandate air filters.
The controversy about ventilation reached Dáil Eireann last week in the form of a bill introduced by People Before Profit TDs. Leaving school windows open helps, but it is winter and opening the windows means keeping the heating up full blast, while getting young kids to wear masks all day is a challenge.
Air filters are more compliant than nine-year-olds, basic designs are inexpensive, and some schools have gone ahead and installed them anyway.
Their use has been recommended by architects and engineers who specialise in ventilation; international studies have long been available which testify to their effectiveness.
Last March the Journal of the Royal Society of Medicine summarised the available evidence like this: “Good ventilation in classrooms is crucial to dilute and filter out respiratory particles to reduce the risk of infection.”
The policy advice was: “Improving indoor air quality in classroom spaces should be followed at the same level as government advice regarding social distancing, mask wearing and hand washing to lower the risk, using natural and/or mechanical ventilation, if possible, with filtration.”
This advice has not been followed in the UK and the websites of leading British virologists have been filled with foreboding since the schools returned after the summer. They did not believe the schools were safe without masking and better ventilation. As in Ireland, the UK infection figures have not supported the ‘schools are safe’ narrative.
The Irish Government’s reluctance to endorse air filters reflects scepticism from a Department of Health medical advisory group despite contrary advice seven months ago from another group chaired by John Wenger, professor of physical chemistry at UCC.
Professor Wenger’s position seems, to this inexpert observer, to be more in line with the international evidence and his position has been supported by Orla Hegarty, an architecture professor at UCD. The Government seems to have chosen the advice, hostile to air filters, from medics over specialists on buildings and air circulation.
Could it be that installing better air filtration in every classroom would be too costly, and not worth the money if the benefits are modest?
If so, there has been a rare and unlikely win for the penny-pinchers.
This Government cannot be accused of unwillingness to spend. Last week saw €2bn allocated for repairing homes built with dodgy bricks in the northwest, while the employment and enterprise support schemes have been costing up to a billion a month.
According to heating and ventilating engineers, a plain vanilla Hepa filter costs, for a large room, up to about €500. With roughly 40,000 units required for the country’s 3,300 primary schools, the cost would be a once-off €20m at maximum. If Hepa filters are effective in mitigating transmission in schools, and the evidence from the experts is that they are, the expenditure of just €20m should not be even a minor deterrent.
There are 535,000 primary school pupils. Even if the risk reduction is limited, any reduction at all would justify spending less than €40 per pupil protected. The modest cost of Hepa units explains why some schools have chosen to bear it themselves and have been installing filters without government funding.
Modern buildings can aspire to something better than the simple Hepa filter, and architects and engineers are already designing and delivering new office buildings to higher ventilation standards than are specified in the building regulations.
Systems which require ducting and external air input can run to several thousand per room for a retrofit in exchange for better performance, according to the heating and ventilation companies.
It appears that schools built in recent years have not been required to meet these ventilation standards. But even at a few thousand a pop, this is not an intimidating level of cost. All that can be done this winter appears to be the plain vanilla filters favoured by People Before Profit, since retrofitting on a large scale would take time in current circumstances given the labour shortages in construction.
But the comforting prospect that the pandemic will be consigned to history by vaccination alone is receding, given new virus variants and the slow take-up of vaccination in many economically advanced countries.
If Covid becomes endemic, as many virologists expect, then spending public money on making buildings safer should prove cheaper than footing the medical bills. Kids get Covid in mild form, but there is worrying evidence about longer-term effects.
The Government needs to explain why the installation of simpler filters in schools is not worth the modest cost involved. If schools and other buildings can be retrofitted with ventilation systems that can deliver superior outcomes, there is time to put a programme in place for next winter.
Public confidence in policy weakens whenever the choices made seem arbitrary. Remember the 5km rule?
There is no point appealing to the scientific evidence if there is none.
The scientific evidence that vaccines work is hugely persuasive. Rigorous clinical trials were conducted before authorisation, followed by the accumulation of evidence since widespread vaccination was undertaken, in sharp contrast to unsupported assertions about the safety of schools and the unimportance of ventilation.
Last week the incoming German government announced, with the support of Angela Merkel’s departing Christian Democrats, that tighter restrictions will now be enforced.
There will be no spectators at the game between Bayern Munich and Barcelona on Wednesday, for example. The rate of new infection which has triggered such alarm in Germany, is no higher than the recent rate in Ireland, where the response has been far less decisive.