Infectious circulation of the Covid-19 virus is due to peak on Saturday, according to a modelling expert.

Software developer Ben Fairfax from Port St Mary has applied the standard SEIR model (susceptible-exposed-infectious-recovered) to give peak dates for infection and hospitalisation.

He says vulnerable people should take action now.

’Shielders should try to avoid high-risk situations,’ Dr Fairfax told the Manx Independent.

’The message is clear and we have a duty to get it out to the public.’

He predicts peak infection day will be Saturday, July 31.

Peak infection actively circulating will be on August 2.

As a result, the peak hospitalisation is due on August 18, with a predicted 22 occupied beds.

Health Minister David Ashford said that all statistical modelling should be treated with caution.

At the start of the pandemic last year, the Manx government made great play of modelling and issued graphs predicting the numbers infected and hospitalisations.

Then the number one priority was to keep pressure down on hospitals by ’flattening the curve’.

In fact, the situation was much better than the models predicted and the Isle of Man was able to come out of the first lockdown on June 15 last year.

Now the government’s policy is different. It is not using modelling at all.

Mr Ashford has repeatedly said that the issue is no longer the numbers. The vaccination of so many elderly and vulnerable people effectively means that the hospital will not be overwhelmed.

Dr Fairfax said he wanted to get his SEIR model into the public domain.

He said: ’My model can tell you about the number of infections that are going to occur and the period over which they will occur. It’s a model for how this will evolve. I think it’s better for people to know where they are going. There is light at the end of the tunnel.’

Dr Fairfax has been developing similar models for the financial markets for the past 16 years. Before that, he set up and ran a software firm producing algorithms for clients that included Goldman Sachs and Morgan Stanley.

He said: ’Certainly there are (a few) more qualified and experienced people than me in the world to produce such models for the Isle of Man. I only worked towards getting a calibrated SEIR model out into the public domain after being informed by a member of EAG that they had not been presented with any such modelling.’

The Emergency Advisory Group, a group of medics, experts and charity workers which advises the government, said that the Delta variant was out of control in the island and mitigation measures don’t go far enough.

wave

Dr Fairfax says the Isle of Man is undergoing a natural wave ’where Covid will move through the low risk groups until we reach herd immunity’.

More than 85% of the population needs to be doubly vaccinated to achieve herd immunity, if current theories prove to be correct.

Mr Ashford said: ’There is a wide range of modelling tools available for epidemic outbreaks and Covid in particular, some of which are openly available for people to utilise and interact with. These tools have been available throughout the pandemic.

’There should however be caution applied to interpreting any outcomes from these as, even with the best data and expert knowledge, they only present a model of one scenario, and can never accommodate the wide variety of factors, human behaviours and the impact small events can have on a small population.

’If it was easy, countries around the world would all have agreement on how best to tackle the difficult decisions they have faced.’

He added that there were experts in epidemiology, public health responses and infectious disease modelling who fed into command structures around the world and often produced models in support.

The independent SAGE group in the UK had subgroups including SPI-M and SPI-M-O that specifically considered the latest thinking, models, and potential outcomes and brings together significant expert opinion.

Mr Ashford added: ’It is notable that this expertise is highly specialised and even across these experts often has a wide range of different opinions, assumptions and ultimately outcomes.

’The models regularly change and have a wide range of assumptions and interpretations.

’In terms of this type of SEIR model (susceptible-exposed-infectious-recovered), there have been many papers published that challenge their appropriateness when compared to observed outbreaks and the SAGE minutes from July note the challenges in modelling the current situation.

’The island’s own focus has moved on from trying to eliminate cases and instead our responses try to mitigate the effects that the virus brings and through a strong identification, testing and isolation approach, containing cases within manageable numbers that do not threaten our health and care systems so that anyone who needs access to care is able to get it, whether that be from Covid or indeed other illnesses.

’We are unable to comment on any particular model, other than to caveat as above that this is a highly specialised field that can only ever get potential hypothetical outcomes based a wide range of subjective opinions.

’Instead the Department of Health and Social Care and Manx Care will continue to regularly monitor the active cases, consider the cohorts involved and forward plan to ensure that capacity for care is going to be available when needed for those who require it.

’It will also, together with Public Health, continue to monitor the evidence that continues to develop around the world and adjust its underlying planning assumptions accordingly.’