Omicron has higher asymptomatic carriage

On 26 November 2021, WHO designated the variant B.1.1.529 a variant of concern, named Omicron, on the advice of WHO’s  technical advisory group on virus evolution (TAG-VE).
This variant of the coronavirus has a higher rate of asymptomatic “carriage” than earlier variants. Both studies found a higher rate of infection than during previous outbreaks, and a higher proportion of asymptomatic carriers.
Both studies are part of larger ones. ‘Ubuntu’, in sub-Saharan Africa, aims to evaluate the effectiveness of Moderna’s vaccine in people living with HIV. The other study is a sub-study of the ‘Sisonke’ study evaluating the effectiveness of Johnson & Johnson’s vaccine.
In Ubuntu, 230 participants were initially screened in December, and 31% tested positive, all of whom were later confirmed to be Omicron. “These data are in stark contrast to Covid-19 vaccine studies conducted pre-Omicron, where the SARS-CoV-2 PCR positivity rate at the first vaccination visit ranged from <1%-2.4%,” said the study, ‘High Rate of Asymptomatic Carriage Associated with Variant Strain Omicron’, currently posted on a pre-print.
In the sub-study of Sisonke, the mean asymptomatic carriage rate among 577 participants was 16% during the Omicron period, compared to 2.6% during Beta and Delta outbreaks. The results suggest a high carriage rate even in those vaccinated, the South African Medical Research Council said in a release.
The most effective steps individuals can take to reduce the spread of the COVID-19 virus is to keep a physical distance of at least 1 metre from others; wear a well-fitting mask; open windows to improve ventilation; avoid poorly ventilated or crowded spaces; keep hands clean; cough or sneeze into a bent elbow or tissue; and get vaccinated when it’s their turn. 
References
1. https://indianexpress.com/article/explained/omicron-has-higher-asymptomatic-carriage-studies-7718400/
2. https://www.who.int/news/item/28-11-2021-update-on-omicron

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