Delta variant to be dominant in Ireland in a fortnight

Dr Cillian De Gascun urged people to get their full two doses of the Covid-19 vaccine as it will help fight against the Delta variant.

The Delta variant will be dominant in Ireland by the middle of July, a leading health chief has said.

Dr Cillian De Gascun, director of the National Virus Reference Laboratory, said the increase of the variant over the last two weeks will “almost certainly lead to Delta dominance by the middle of July”.

Dr De Gascun said this could lead to “a consequent increase in case numbers, hospitalisations, and mortality in the following weeks”.

It comes as the Government delayed plans to reopen indoor dining in the hospitality sector until at least July 19.

The Taoiseach said in announcing the delay that the country is now in a race between the variant and the vaccines.

The National Public Health Emergency Team (Nphet) advised the delay, citing concerns around the rise of the Delta variant.

It predicted that we could see up to 2,170 Covid-related deaths across July, August and September as the Delta variant spreads across the country.

In a long thread on Twitter discussing the variant, Dr De Gascun said that it “exhibits an increased growth rate, an increased secondary attack rate, increased household transmission, and laboratory evidence of increased replication in biological systems that model the human airway” when compared to the Alpha variant.

The Alpha variant has been dominant in Ireland for the last five months.

“We can say that Delta is almost certainly at least twice as transmissible as the virus we experienced last summer,” he said.

“The case-fatality rate for Delta (0.3%) at this time appears to be lower than that for Alpha (2%). 

"However, a large number of cases are still within the follow-up period, so we still have more to learn about the clinical course of disease with Delta infection.” 

Vaccines

Dr De Gascun urged people to get their full two doses of the Covid-19 vaccine as it will help fight against the Delta variant.

“We do see a reduction in vaccine effectiveness (VE) for Delta compared with Alpha against symptomatic infection, particularly after one dose.

“Although this is concerning, VE against Delta is high after two doses, and VE against hospitalisation is maintained.” 

He added that, unlike last summer, we now have “very effective vaccines”.

Dr De Gascun added: “The key is to protect each other through established public health interventions (hand hygiene, distancing, mask-wearing, managing number of contacts) while the vaccines take effect.

“Please remember that you are not fully vaccinated until 2 weeks after your second dose of ChAdOx1 Astra Zeneca vaccine, or 7 days after your second dose of Pfizer/BioNTech vaccine. 

"Two doses are required for optimal protection against the Delta variant.”

Dr De Gascun also highlighted how in the UK, Delta is the dominant variant, “accounting for approximately 97% of cases.

“As a consequence, case numbers, hospitalisations, & deaths have increased in recent weeks.” 

He added: “The proportion of cases due to Alpha in Ireland has declined from 91% in week 23 (beginning June 7) to 45% in week 25 (beginning June 21).

“Alpha cases yield S gene negative results on this assay; Delta cases yield S gene-positive results. Based on the transmissibility data described earlier, it is probable that the vast majority of our S gene-positive cases (i.e. 55%) are Delta. “

It comes as last night, the Department of Health confirmed a further 351 new cases of Covid-19 in Ireland.