What has the UK learned about Omicron from South Africa?

There is now community transmission of the Covid-19 variant Omicron in the UK, Sajid Javid told MPs yesterday.

The health secretary said the new strain, which was first detected in South Africa, is “continuing to spread here and around the world”, ITV News reported. The 336 confirmed cases in the UK includes people whose infection has no link to international travel.

With at least 52 countries now affected, many are looking back to South Africa for early clues about what the variant means for their nations.

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The early data

A new report from the South African Medical Research Council, released on Saturday, suggests the new strain could cause a milder infection based on several factors, including in-hospital death rates, the level of care required in hospital, oxygen use and the length of stay in hospital.

So far, early data from the Steve Biko/Tshwane District Hospital Complex in Pretoria, in Gauteng province where Omicron was first detected, suggests there has not been a significant increase in in-hospital deaths despite a “dramatic” rise in the number of cases in the province.The report did warn, however, that this could be due to a lag between cases and deaths – a more definite trend will become apparent in the coming weeks.

The report also noted that the majority of patients – around 70% – were not oxygen-dependent and that most of the patients had been admitted to hospital for medical reasons other than Covid-19.

Another marked difference with the Omicron strain appears to be the age profile of those infected. At the moment it appears to affect younger people than previous prevalent strains of the virus.

An analysis of 166 patients admitted to the hospital between 14 and 29 November found that “no fewer than 80% of admissions were below the age of 50 years”, while 19% of those infected were children aged nine and below. The highest number of admissions came from those in the 30-39 age group, which made up 28%.

However, the report said that it was “essential to recognise” that the data only covered the first two weeks of the Omicron wave in Tshwane (Pretoria), warning that the “clinical profile of admitted patients could change significantly over the next two weeks, by which time we can draw conclusions about the severity of disease with greater precision”.

The significance for the UK

It is “difficult to draw conclusions” about the implications of the data coming out of South Africa for other countries such as the UK, given that South Africa has a “much younger population that is less likely to be vaccinated”, said Sky News. According to Our World in Data, less than 30% of the population has at least one vaccine, compared with 75% of the UK.

And there is little evidence yet that Omicron is “inherently a more mild strain”, cautioned John Burn-Murdoch, chief data reporter for the Financial Times (FT).

What the data does seem to bear out is that the variant is “more mild for people with immunity from either recent vaccination or infection”, he wrote on Twitter. This means that while Omicron’s mutations could affect protection against infection, it appears that vaccinations are still very effective in protecting against severe illness.

A point of concern remains that Omicron-driven hospitalisation rates are rising much faster than in previous waves, which in turn could drive up ICU admissions, even if the majority experience a much milder illness.

“Even if far less than 25% of patients require ICU this time, a small share of a rapidly increasing number can still become a big number. And numbers are going up very, very fast,” said Burn-Murdoch.

“With governments very reluctant to reimpose major restrictions, Omicron’s growth advantage (whether conferred by shorter incubation period, immune evasion and or something else) is bound to produce very rapid waves of infections when it takes hold.”

Government officials and scientific advisers in the UK believe that the severity of the Omicron variant “may not be clear until January”, reported The Guardian.

There is a “wariness about overreacting” in government but senior Sage scientists have “made the case privately that the additional precaution of home working should be taken in the run-up to Christmas and that the government should start to suggest that people take sensible steps to minimise social contact in the days before seeing loved ones”, said the paper.

But so far Boris Johnson has advised that the country presses ahead with Christmas plans, including parties and school nativity plays.