Covid-19: Given the inevitability of delta becoming dominant, what should we do?

Analysis: Given the threat posed by the new variant it may be time to deviate from an age-based approach to vaccine rollout

Suggestions that the next phase of easing restrictions should be delayed due to the threat posed by the delta variant of Covid-19 will be irritating for some, and financially disastrous for others.

After all, wasn’t our lockdown prolonged by the “abundance of caution” approach? Weren’t we asked by the National Public Health Emergency Team to delay earlier relaxations of measures in the spring for several months until more people were vaccinated?

Haven’t most vulnerable people been offered a vaccine by this stage? And hasn’t the link between cases and hospitalisations been broken thanks to widespread vaccination?

This is all true. There are no outbreaks at present in nursing homes or hospitals. Incidence of the disease is lower than it has been since last September, as are hospital and ICU numbers.

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Yet when the evidence changes you have to change your approach. The question now is whether the threat posed by the delta variant has changed things to such a degree as to justify delaying the easing of restrictions next month.

We can see what is happening at present, in the latest twist this pandemic is taking, even if comprehensive data is lacking.

The variant is taking over because it is more transmissible, just as the alpha variant from the UK took over after Christmas last year. That took four to six weeks, and it shouldn’t take the delta variant much longer to do the same.

This is an inevitable process, a sort of Darwinian natural selection “on speed” as a fitter strain of the virus gets the upper hand. We might push the process back by a few weeks, during which more people can be protected through vaccination, but the end-result will be the same.

The variant is already dominant in countries as diverse as India, the UK, Singapore, Russia and Indonesia. At some point in the future, it will be displaced by an even fitter, possible more dangerous variant.

Based on early data, the variant is estimated to be 40-60 per cent more transmissible than the alpha variant. It is too soon to say conclusively whether it is more lethal.

Across the UK, the number of Covid-19 patients in hospital is on the rise again as cases surge. Israel, ahead of the world on vaccination, may re-introduce a requirement to wear masks indoors from this weekend due to a surge in variant cases.

Here, we have yet to see a rise in overall case numbers. In the coverage of concerns about the variant this week, the fact that overall infections were dropping was overlooked.

This may change, but cases are likely to grow most among younger people because they are not vaccinated; most of these will be mild infections.

Given the inevitability of delta becoming dominant, what should we do? The vaccination rollout is proceeding as fast as it can, based on supplies available. The interval between AstraZeneca doses is being cut, because people with only one dose are poorly protected against the variant.

Delaying the easing of restrictions for three weeks would allow about 1 million doses to be administered, half first doses and half second doses.

Should we also prioritise teachers for vaccination, in time for their return to the classroom? Or, more immediately, barworkers facing the return of indoor dining in July?

Can we make better use of our vaccines to maximise protection? For example, with studies showing reduced effectiveness against hospitalisation for the AstraZeneca vaccine, should we give a second dose of another vaccine to people who got a first dose of AstraZeneca? Many of these are vulnerable 60-somethings still waiting for a second dose, long after younger people have been fully vaccinated.

With an oversupply of AstraZeneca likely after mid-July, we could make this vaccine available to anyone who wants it, so that young people - the cohort where most cases are occurring - can avail of it.

Up to now, we have been slow to deviate from an age-based approach to vaccine rollout, but given the threat posed by the variant, it may be time for a change.

Difficult decisions will have to be made about vaccinating children, however slight the risk most of them face. The latest evidence from the US, showing an elevated number of heart inflammation cases among young males who had received an mRNA vaccine, shows that for many, the risks of taking a vaccine could outweigh the individual benefit.

Ultimately, Government will have to make the decision - and soon. Comparisons with other countries tell us only so much - we have fewer variant cases, but also fewer vaccinated, than the UK.

The answer may lay elsewhere. Public health has performed well in tracking outbreaks since the spring. Effective testing and contact tracing are fundamental parts of a sustainable response to the virus; yo-yo restrictions are not.

Paul Cullen

Paul Cullen

Paul Cullen is Health Editor of The Irish Times