THE GOVERNMENT HAS announced an acceleration of the Covid booster programme, as emerging evidence indicates reduced protection from vaccines against the new Omicron variant.

Many countries had, before the new variant emerged, been operating booster programmes similar to Ireland’s, focusing on vulnerable groups, with a gap of five or six months between the second dose and a booster.

However, in a statement this evening, Health Minister Stephen Donnelly announced that the gap between your Covid jab and your booster injection has been reduced from five to three months. 

“I have this evening accepted a recommendation from NIAC that the gap between completion of the primary schedule of COVID-19 vaccination and a booster dose will be reduced to three months. Boosters will continue to be offered in the priority order previously recommended,” he tweeted today.

This five/six month interval was based on studies which began to emerge in the autumn and which showed waning immunity among those who were vaccinated. However the Omicron variant has changed the discussion. 

Now it is less about immunity to the Delta variant waning after a period of time and more about generally reduced immunity to this new variant across all vaccinated cohorts.

The National Immunisation Advisory Committee (NIAC) has recommended a booster (fourth dose) of an mRNA vaccine no sooner than three months after their third dose for those who are immunocompromised and for whom a third dose had been previously recommended as part of an extended vaccine schedule.

NIAC also recommended that those individuals who have received one dose of a two-dose primary vaccine schedule and who subsequently got Covid, should complete their primary vaccination course four weeks after their diagnosis or when they started to get symptoms.

The Journal reported last week that the plan was to be accelerated for the 30s and 40s age cohorts. 

Fresh advice from the European Medicines Agency (EMA) last week stated that data currently available supports safe and effective administration of a booster dose as early as three months from completion of the primary vaccination, should such a short interval be desirable from a public health perspective.

Vaccine efficacy

Pfizer-BioNTech last week presented preliminary results from a study, warning that  ”the Omicron variant is probably not sufficiently neutralised after two doses”.

Blood samples from around 20 people who had received two doses of the current vaccine showed on average a 25-fold reduction in neutralising antibodies compared to the early strain of the virus, the companies said.

However they added that another part of the immune response – from T-cells – were probably still effective against the new variant, meaning that people with two doses “may still be protected against severe forms of the disease”.

The companies said the study indicates that three doses of the vaccine are effective against the Omicron variant.

Results showed a booster generated around the same level of potent antibodies against Omicron as is seen after a second dose with the initial strain.

Preliminary results from another small study in South Africa suggested there was up to a 40-fold drop in the ability of the antibodies from the same vaccine to neutralise Omicron, compared to an early strain.

However the institute which carried out the study said it was important to be careful interpreting results because they reflect what happens in a laboratory setting and real-world data will be the true test. 

International response

Several other countries have also decided to reduce their wait time in response to the new variant. 

South Korea has just announced that it will further cut its booster interval for all adults to three months, as the country reported more than 7,000 new cases for three days in a row.

Thailand has also decided to halve to three months the time between administering a second dose and a booster.

In the US, eligibility for Covid booster vaccines has been expanded to 16 and 17-year-olds at least six months after their second vaccine dose. 

Australia has just cut its waiting time from six months to five for anyone aged over 18. 

Many EU countries still have a five-month interval, though this may change over the course of the week as further information about the Omicron variant emerges and case numbers rise.

Others have already made the move to reduce the wait time, with Greece announcing earlier this month that the interval was to be cut to three months. 

- With reporting from AFP and Garreth MacNamee