COVID-19 CASE numbers are likely to increase as restrictions ease, but this does not mean the vaccines are not effective, Dr Cillian De Gascun has said. 

In a Twitter thread last night, the Director of the National Virus Reference Laboratory said that the vaccines are not sufficiently effective, on their own, to suppressing or eliminating Covid-19 transmission in the community. 

However, he said “they are very effective at protecting against hospitalisation and severe disease”. 

De Gascun’s comments come as a number of meetings are due to be held over the coming days ahead of a decision on whether to lift all remaining restrictions on 22 October. 

Public health officials yesterday confirmed a further 2,180 cases of Covid-19 in Ireland. 

De Gascun said that while the vaccine level in high among those aged over 12, across the population as a whole around 75-80% of people are vaccinated.

“On that basis, and taking into account the cohort of the population that is not (yet, at least) eligible for vaccination, we can see that the current first generation of [Covid-19] vaccines is unlikely – in isolation at least, ie. without additional public measures – to be able to control .. Delta in the community,” De Gascun said. 

It simply means that they are not sufficiently effective – on their own – to suppress or eliminate #SARSCoV2 transmission in the community. However, they are very effective at protecting against hospitalisation and severe disease 16/n

— Cillian De Gascun (@CillianDeGascun) October 17, 2021

“We will continue to see case numbers increase as restrictions ease. This does not, and I stress, does not, mean that the #SarsCov2 vaccines are not effective,” he said. 

“It simply means they are not sufficiently effective – on their own – to suppress or eliminate #SarsCov2 transmission in the community.” 

De Gascun said added: “Whilst vaccination reduces the risk of Delta infection, fully vaccinated individuals have viral loads similar to unvaccinated and can effectively transmit infection in household settings, including to fully vaccinated contacts.”

In a separate Twitter thread yesterday, Professor Philip Nolan who is also chair of the NPHET Irish Epidemiological Modelling Advisory Group, said the balance had “tipped in the wrong direction” but that change in behaviour would bring down the reproductive number of the virus, below 1.0, and start to suppress it once again.

The increase over the last 10 days shows that this balance has tipped in the wrong direction: with high levels of circulating virus even a subtle change in the scale or nature of social contact can significantly shift the dynamics of viral transmission in the population. 6/16

— Professor Philip Nolan (@PhilipNolan_MU) October 16, 2021

Nolan that Ireland had been left in a “vulnerable position” following the vaccination of 16-30 year-olds in the summer, with high levels of infection still present among younger age groups while “increasing levels of social contact” were beginning to take place. 

“…This left us in a vulnerable position, with high levels of infection, and that delicate balance between very high levels of vaccine protection on the one hand, and increasing levels of social contact and risk of transmission on the other,” he said.

“The increase over the last 10 days shows that this balance has tipped in the wrong direction: with high levels of circulating virus even a subtle change in the scale or nature of social contact can significantly shift the dynamics of viral transmission in the population.”

Nolan added: “This also means that a relatively modest adjustment in our individual and collective efforts to reduce risk of transmission should be enough to shift the balance in the opposite direction, bring effective reproduction number below 1.0 and start to suppress the virus again.”

With reporting by Eoghan Dalton