Covid-19 cases set to increase due to new subvariants, ECDC warns

Ireland has genetically sequenced a higher proportion new BQ.1 subvariant than most European countries

Covid-19 cases are set to rise in Ireland and other European countries within weeks due to the rise of a new subvariant of the virus, the European Centre for Disease Control has warned.

Ireland has genetically sequenced a higher proportion of cases of the new BQ.1 subvariant than all other European countries bar two, it said on Friday.

Preliminary lab studies in Asia show BQ.1 has the ability to “considerably” evade the immune system response, the ECDC pointed out.

Five EU states had detected the new subvariant by the first week of October; it accounted for 19 per cent of cases in France, 9 per cent in Belgium, 7 per cent in Ireland, 6 per cent in The Netherlands and 5 per cent in Italy.

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“The current proportions are not high enough for the variant to already have had a noticeable impact on the epidemiological situation in the affected countries,” the ECDC said in a statement

BQ.1 and BQ1.1 will become the dominant strain in the EU by mid-November to the beginning of December, ECDC modelling forecasts, and this will “likely contribute” to a rise in cases “in the coming weeks to months”.

There is no evidence from the limited data available of BQ.1 causing more severe illness compared to the currently circulating Omicron variants.

At least 40 cases of BQ.1/BQ1.1 have been detected in Ireland, according to the Health Protection Surveillance Centre.

ECDC director Andrea Ammon called on countries to be vigilant and to prioritise Covid-19 boosters for at-risk groups.

Its warning comes as the current wave of Covid-19 infections Ireland appears to be levelling off, with both case numbers and hospitalisations starting to fall.

If confirmed over the coming weeks, the trend will be in line with neighbouring European countries which have already seen a late autumn wave of infections taper off. Even before the ECDC bulletin, experts were warning of the likelihood of a further wave driven by new variants.

The number of people with the virus in hospital had been rising since mid-September, but this growth has petered out in the past week. There were 442 Covid-19 patients in hospital on Friday, compared with 470 last Monday and 434 the previous Friday.

Fewer than half the hospitalised patients testing positive for Covid-19 are there because of the virus, but the high number of such patients put pressure on hospitals and increases the risk of other patients picking up infections during their stay.

Admissions of Covid-19 to intensive care have started to increase in the past fortnight, though the absolute numbers are small. There were 16 patients with the virus in ICU on Friday, compared with a low of eight on October 10th.

The latest weekly report from the HPSC, covering October 9th to 15th, recorded a 5.6 per cent fall in positive PCR tests compared with the previous week. Self-reported antigen tests results were stable.

However, the number of outbreaks was up eight, to 52. There were 18 outbreaks apiece in hospitals and nursing homes.

Surveillance data is less comprehensive than it was during the peak of the pandemic as few groups now require PCR testing.

However, the positivity rate of completed tests – an indicator of the amount of infection in the community – has remained broadly stable. Meanwhile, wastewater surveillance for Covid-19 shows a slightly declining trend.

The most recent wave was most likely driven by the arrival of autumn and a return to schools. Experts fear a further wave could be fuelled by the rise of a new variant with greater ability to evade immunity.

Small numbers of new subvariants have been detected, according to chief medical officer Prof Breda Smyth.

BA.2.75, BF.7 and BQ.X show evidence of growth compared with the currently dominant variant, BA.5, according to Prof Smyth’s latest weekly report.

Paul Cullen

Paul Cullen

Paul Cullen is a former heath editor of The Irish Times.