However, scientists also concluded that they are less able to co-exist in the blood of those who received vaccinations to prevent the disease.
The scientists, from more than one institution, examined the PA4 and PA5 subtypes of Omicron, which the World Health Organization added to its watch list last month.
Scientists drew blood samples from 39 participants who had been infected with Omicron when it first appeared at the end of last year, according to Reuters.
Fifteen of them had received preventive vaccinations, 8 with the Pfizer vaccine and 7 with the Johnson & Johnson vaccine, while the rest did not receive a preventive vaccine.
“The group that received the vaccines showed the ability to neutralize the virus more than five times, and therefore they are better protected,” said the study, whose preliminary version was published at the weekend.
In samples drawn from those who did not receive vaccinations, there was an eight-fold decrease in antibody production upon exposure to the two sub-strains compared to the original strain of Omicron PA1.
The blood samples of those who received the vaccine showed a decrease of only three times.