Omicron variant does cause different symptoms from Delta, study finds

People who have the Omicron Covid variant tend to have symptoms for a shorter period, a lower risk of being admitted to hospital, and a different set of symptoms than those who have Delta, according to research.

While the Omicron variant is better at dodging the body's immune responses than Delta, it also produces less severe disease.

A large study has backed up the findings that Omicron is linked to a shorter duration of illness and a different collection of symptoms.

The study comes just days after the National Health Service added nine more symptoms for Covid, including a new and persistent cough, a loss or change in taste or smell, and a high temperature. The researchers found that people who had Covid when Omicron was prevalent were less likely to have at least one of the symptoms.

The co-author of the research from King said that it is a lesson that we need to be more flexible in thinking about what the virus is and how it is going to present in the UK.

The study will be presented at the European Congress of Clinical Microbiology and Infectious Diseases and will be published in the Lancet.

The researchers matched almost 4,990 participants who had a confirmed Covid infection between 1 June and 27 November 2021, when Delta was the most prevalent variant. The experience of both groups was compared.

Symptoms lasted on average 6.9 days when Omicron dominated, compared with 8.9 days when Delta dominated, with infections linked to a 25% lower likelihood of admission to hospital.

When Omicron dominated, the results suggested only a small percentage of people lost their sense of smell, compared to when Delta dominated. A sore throat was more common among the latter.

The approach used in the research should alert us to when the next variant will be.

He said that we need to be more proactive in public health messaging.

The findings chime with what hospitals experienced at the start of the year when the BA.1 Omicron variant dominated, according to Dr David Strain, who was not involved in the study. The picture has changed again since the Omicron variant BA.2 took over.

He said that people in hospital are staying for longer and staff are testing positive for longer so it is longer before they can return to work.

The average prevalence of Covid across England was at the highest level ever recorded. The UK Health Security Agency reported on Thursday that 15.3% of people aged 75 and over have received their spring booster Covid jab so far.