Omicron is spreading “rapidly” in the UK and will most likely lead to increased hospital admissions, scientists advising the government have said.
The minutes of a meeting held Tuesday by the Scientific Advisory Group for Emergencies (Sage) indicate that the proportion of Omicron infections that result in hospitalization cannot be known until there have been more than people hospitalized, but even if there was a “modest reduction in severity” of the disease compared to the Delta variant, it “would not prevent a high number of hospitalizations if the growth rates remained very high.”
Scientists said Omicron would likely account for the majority of new Covid infections in the UK “in a matter of weeks” and could partially or largely replace Delta, which is currently the dominant variant.
In its own assessment, the British Health Security Agency (UKHSA) said it is likely that Omicron will become the dominant strain in Britain and it expects at least 50% of Covid cases -19 be caused by Omicron in the next two to four weeks. .
The Sage paper said: “Although there are several unknown factors, preliminary modeling suggests that without any changes to the measures in place, the number of Omicron hospitalizations could reach 1,000 per day or more in England. here the end of the year (and still be increasing at that time).
“The overall magnitude of any wave of hospitalizations without interventions is very uncertain, but the peak could reach several times that level.”
Currently around 769 patients per day are hospitalized in the UK.
Advising the need for ministers to consider restrictions, Sage added, “The peak is most likely over 1,000 to 2,000 Omicron hospital admissions per day without intervention to slow the rate of the rise in infections; to be below this level would require only a low degree of immune evasion and very high protection against boosters against Omicron.
Sage said hospital admissions are much more likely to be affected by a rapidly spreading variant and that she manages to evade vaccine protection than any change in its severity from Delta.
“With lags of the order of two weeks or more, and doubling times of the order of three days, it is likely that, once hospitalizations start to increase at a rate similar to that of cases, four doublings (a 16-fold increase) or more could already be ‘in the system’ before interventions that slow infections result in hospitalizations, ”the experts added.
Sage estimated the doubling time for new Omicron infections to be about three days in England, adding: “The mechanisms underlying the growth rate advantage of Omicron remain unclear.
“The increase in transmissibility and the evasion of immunity (after infection and / or vaccination) are likely to play a role, although the relative contribution of each of these factors, or any other factor, is not still known. “
Experts have suggested that finding and isolating cases through contact tracing may become less effective if people become infectious earlier, as some scientists have suggested.
“This would increase the relative importance of population-based rather than case-based measures, namely measures that affect everyone, not just those who are confirmed to be infected.”
Evidence of so-called ‘super-spreading’ events “also suggests a greater role for airborne transmission than before,” Sage said.
He added: “This means that measures to reduce airborne spread such as ventilation, properly fitted masks and the remoteness or reduced density of people in indoor environments can be even more important.”
In an assessment prepared for Sage, the Scientific Pandemic Influenza Group on Modeling, Operational subgroup (SPI-MO) stated that “any significant wave of infection, almost regardless of immune breakout, will affect hospitalizations.
“If South Africa’s initial estimates of the benefit of transmission and immune evasion are applicable to the British population, there is a potential for a much larger spike in infections than that recorded in January 2021.
“Even if Omicron’s severity was half that of Delta, the sheer number of infections could put much greater strain on healthcare and care facilities; currently, there is no strong evidence that Omicron infections are more or less severe than Delta infections. “
The group said that if Omicron’s immune breakout reduced the effectiveness of the vaccine against hospitalization from, say, 96% to 92%, “it would effectively double the number of people vaccinated who are not protected against the disease. hospitalization”.
In a statement, Dr Susan Hopkins, Chief Medical Advisor of the UK Health Security Agency, said: “There is growing evidence that Omicron is highly infectious and there is laboratory evidence and early clinical evidence for it. suggest that the vaccine-acquired and naturally acquired immunity to infection is reduced for this variant.
“So it’s absolutely essential that we all do everything we can to help break the chains of transmission and slow the spread of this new variant.
“Vaccination is essential to help us strengthen our defenses against the serious illnesses caused by this new variant – please get your first, second, third or booster without delay.
“Please also be sure to follow all government guidelines to reduce the spread of infection.
“It remains vital that anyone with symptoms of Covid-19 self-isolate and receive a PCR test immediately. “