The percentage of global cases of the delta variant of the coronavirus is falling for the first time since it was baptized as such in April, while the omicron continues to rise and is already present in outbreaks of community transmission, the World Health Organization (WHO) warned.
In its weekly epidemiological report, the agency emphasizes that although most of the omicron cases identified since November in more than 70 countries are related to travel, there are already sources of contagion in the same community.
The WHO also highlights that the delta variant, which by mid-year was already the dominant one in the world and before omicron reached 99.8% of the sequenced cases, has dropped that percentage to 99.2% in the last measurement performed by the global network of laboratories GISAID, which collaborates with the WHO.
Of the 879,000 cases sequenced in the laboratory by the network in the last 60 days, a great majority (872,000) were still of the delta variant, but the omicron already represented 3,755 cases (0.4%), when a week ago that percentage was 0.1%, which indicates a rapid progression.
Current evidence, the report adds, seems to indicate that the variant omicron it has evolutionary advantages over delta when it comes to transmitting and is doing so faster.
This has been noticed not only in countries with a relatively low incidence of delta cases, such as South Africa, the first country where the new variant was detected, but also in others where the coronavirus delta was at high levels, like the United Kingdom, added the investigation of WHO.
In his omicron analysis, the WHO reiterates that the variant seems to affect the effectiveness of vaccines against infection and transmission, and with it also increases the risk of reinfection (the possibility that a person who has had COVID-19 will suffer it again).
Preliminary studies independent of the WHO have shown that omicron reduces the protection against reinfection of four of the main anticovid vaccines, those produced by Pfizer-BioNTech, Moderna, AstraZeneca and Johnson & Johnson.
However, the variant does not seem to affect the PCR tests for detection of the virus, which can help to monitor its progress, while treatments against severe or critical cases of COVID-19 “should continue to be effective” against omicron, indicates the WHO.