Omicron has higher ‘asymptomatic carriage’ rate than previous outbreaks, finds studies

The newest variant of concern, probable cause for surge in Covid-19 cases in India has a higher rate of asymptomatic “carriage” that earlier variants and also a higher rate of infection than earlier outbreak. The findings were a part of bigger studies conducted to find the effectiveness of Moderna vaccine on people affected by HIV in sub-African ‘Ubuntu’ and another to evaluate the effectiveness of Johnson and Johnson vaccine.

Who are asymptomatic carriers?

According to WHO, laboratory-confirmed cased where a person is infected with Covid-19 but shows no symptoms are asymptomatic carriers. But even without symptoms they can infected another person and should be isolated to limit their contact and break the chain of infections.

Here’s what the findings of study in ‘Ubuntu’ suggest

A total of 230 subjects were tested in December and 31 per cent tested positive, all with the Omicron strain. The positivity rate was in stark contrast with studies conducted before Omicron was detected in South Africa when the positivity rate at first vaccination visit was between 1 and 2.4 per cent.

Here’s what the findings of study in ‘Ubuntu’ suggest

A total of 577 participants were studied and the mean symptomatic carriage rate was found to be 16 per cent during the Omicron period, much higher than in Beta or Delta outbreak at 2.6 per cent. The South African Medical Research Council found that the carriage rate is higher even in those vaccinated.

The study quoted Dr Lawrence Corey who advised on wearing mask, washing hands, avoiding large gathering and getting fully vaccinated to stay safe as knowing who is carrying the virus is difficult in the times of Omicron outbreak.

The researchers added that higher asymptomatic carriage rate is likely to be a major factor in rapid and widespread dissemination of variant even among populations with high rate of coronavirus infection.