Infection with the new coronavirus, two or three times, may become more frequent with the spread of the Ômicron variant around the world. The highly transmissible strain was first reported to the World Health Organization (WHO) by South Africa on 24 November.
A study conducted by researchers at Stellenbosch University in South Africa indicates that the variant currently dominant on the planet is associated with a greater ability to reinfection compared to other strains of the virus. The results were published in the journal Science.
According to the study, a total of 105,323 suspected reinfections were identified among 2,942,248 laboratory-confirmed individuals who tested positive at least 90 days prior to January 31, 2022.
The number of reinfections observed until the end of the third wave in the country, in September 2021, was consistent with the absence of changes in the risk of reinfection. Although increases in the risk of primary infection were observed after the introduction of Beta and Delta variants, no associated increase was observed in the risk of reinfection.
According to the analysis, the estimated risk rate for reinfection compared to primary infection was lower during the waves driven by the Beta and Delta variants than for the first wave.
On the other hand, the spread of the Ômicron variant, starting in November 2021, was associated with an increase in the risk coefficient of reinfection. The researchers identified that individuals with reinfections detected since November 1, 2021 have experienced primary infections in all three previous waves, with an increase in third infections seen since mid-November.
Escape from the immune response
Evidence suggests that the Omicron variant is associated with a significant ability to escape the immunity conferred by previous infections. On the other hand, there is no epidemiological evidence of immune escape associated with Beta or Delta variants, according to the study.
In addition, the Ômicron variant is not able to fully circumvent the immunity and protection offered by vaccination. WHO technical director Maria Van Kerkhove said in an interview with the “Science in 5” podcast that vaccines remain “incredibly effective in preventing serious illness and death, including against the most recent variant of concern, Ômicron”.
The researchers argue that the results may have implications for public health planning, particularly in countries such as South Africa, with high rates of immunity to previous infections.
Experts recommend the development of methods to track the risk of reinfection during the emergence of new strains, including refinements to assess the impact of waning immunity, account for vaccine-derived protection, and monitor the risk of multiple reinfections.
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Source: CNN Brasil