In its weekly epidemiological update, the organization said that more data is needed to better understand the degree to which “Omicron” eludes immunity resulting from either receiving the vaccine or previous infection.
“As a result, the overall risk of the new mutant in question, Omicron, remains very high,” she added.
And a study published on Tuesday had reported that the three vaccines against the Corona virus, which are authorized for use in the United States, appeared to be significantly less able to provide protection against the Omicron mutant during laboratory experiments.
The study, conducted by researchers at Harvard University and Massachusetts Institute of Technology, Massachusetts General Hospital, which has not yet been reviewed, indicated that it is likely that vaccines will restore their effectiveness against “Omicron” to a large extent through a booster dose.
The study conducted tests on the blood of people who had received the Moderna, Johnson & Johnson and Pfizer vaccines, against a virus designed to resemble the “Omicron” strain.
The researchers found that the ability of antibodies to resist the strain was low or no when obtaining vaccines according to the usual regimens, which are two doses for the Moderna or Pfizer vaccine, or one dose of the Johnson & Johnson vaccine.
The study further found that a blood sample drawn from new recipients of a booster dose showed strong resistance to the strain.
The scientists also suggested that “Omicron” is more contagious than the previous strains of concern, which appeared in the form of a doubling of the susceptibility to infection compared to the currently circulating Delta strain, which may be surpassed by “Omicron” soon.
The findings are in line with other studies published recently, where researchers at Oxford University said on Monday that they found that the two-dose regimen of Pfizer and AstraZeneca vaccines did not stimulate enough antibodies to counter the new strain.
Pfizer also said last week that a three-dose regimen of the Covid-19 vaccine would be able to neutralize the new strain “Omicron” during a laboratory experiment, but having two doses stimulated the antibodies less.
Moderna and Johnson & Johnson have not yet published any of their own data on whether their vaccines are resistant to the new strain.
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