The new variants of omicron BA.4 and BA.5 have the potential to trigger another wave of covidem-19 infections

At the beginning of May, the coronavirus subvariants SARS-CoV-2, known as BA.4 and BA.5, bothered the Republic of South Africa in particular. But as usual, they have gradually spread throughout the world. European Center for Disease Prevention and Control (ECDC) issued a report on Mondayin which he warns that the number of covid-19 diseases is likely to increase in Europe in the coming weeks.

How strong the expected wave of new diseases will be will be influenced by a number of factors. These include, for example vaccination coverage and population prevalencebut also the time that has elapsed since these events, as immune protection in both cases weakens over time.

Will there be another wave?

Omicron subvariants BA.4 and BA.5 have an advantage over previous mutations BA.2 and BA.2.12.1 in even higher infectivity. At least in part, the good news is that so far there is no indication that they cause a more severe course of the disease or higher mortality compared to the circulating variants BA.1 and BA.2.

However, it seems that they are better able to escape immunity acquired by vaccination or previous infectionwhich can lead to recurrent infections. “As in previous waves,” writes ECDC, “The growing number of covid-19 cases may lead to an increase in hospitalizations, intensive care units and deaths.”

ECDC expects that, in view of the expected next waves or before the autumn / winter season, additional booster doses will be needed for the groups most at risk of the disease, such as people over 60 and the chronically ill.

Portugal as a vanguard

Subvariants BA.4 and BA.5 first appeared in South Africa in January and February, and arrived in the EU in March. Recently, their spread has gained momentum. Portugal is the first country to experience a wave of new diseasesas of May 30, BA.5 accounted for as many as 87% of cases.

Click for larger image Numbers infected with covid-19 in Portugal

Severity indicators – hospitalizations, intensive care units and deaths – were below the previous peak due to omicron on 1 June, but a weekly increase is still observed. In the last six weeks, there has been an increase in hospitalizations and hospitalizations in intensive care units, especially for people over 60 years of age.

The incidence of BA.4 and BA.5 is now increasing in Austria, Belgium, Denmark, France, Germany, Ireland, Italy, the Netherlands, Spain and Sweden. In Belgium, BA.5 recently accounted for 19% of sequenced samples and BA.4 for 7.5%. In Spain, BA.4 and BA.5 accounted for more than 10%. In the Netherlands, BA.5 reached 8%, while BA.4 was close to 5%. At the turn of May and June, the laboratories of the State Institute of Public Health demonstrated these two types of omicron in the Czech Republic.

The United States faces similar prospects. Currently, BA.4 and BA.5 are gaining ground behind the BA.2.12.1 variant, which only gained a dominant position in the USA at the end of May. According to the Centers for Disease Control and Prevention, BA.2.12.1 currently accounts for an estimated 62.2% of cases, while BA.4 is 5.4% and BA.5 is 7.6%. Less than a month ago, the pair accounted for about 2% of cases.

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