New strains have broken through previously acquired immunity, whether this was gained from vaccination or recovery from the disease.

"Exactly how high the crest of the new wave will be is difficult to predict because countries are testing significantly less than during the first Omicron wave," Lutsar told ERR.

She said the spikes of infection are not as big as last sprig but this is due to the reduction in mass PCR testing.

"Home rapid tests are used and apparently not all cases of illness are registered," the University of Tartu professor said.

BA.4 and BA.5 are already having severe impacts on health systems in Asia, according to media reports. However, it is not yet possible to create vaccinations targeted at specific strains, Lutsar said.

"We are always a step or two behind the production of these new vaccines. When a vaccine containing a new strain arrives [on the market], those strains are no longer circulating, there are new strains," said Lutsar.

She emphasized that current vaccinations still protect against severe cases of coronavirus.

While neighboring Latvia and Lithuania are seeing a surge in new cases, this spike has not yet been recorded in Estonia, the Health Board says.

Last week, 1,163 new cases were diagnosed (compared to 801, 822 and 840 during previous weeks) and 91 patients were being treated for coronavirus in hospital.

The last time more than 1,000 cases a week were registered was mid-May. It dropped to around 800 after.

--

Follow ERR News on Facebook and Twitter and never miss an update!