Covid-19 infections could double by Christmas, scientists have said informing the government.
The warning is part of the final installment of the Scientific Advisory Group for Emergencies (Sage). The documents were presented to the government ahead of the decision to ease Covid restrictions during the holiday season.
“Notes on Festive Period” was written by the Pandemic Influenza Modeling Science Panel (SPI-M), which cautions the document as being based on preliminary modeling. The document contains stern warnings about a large mix of people over a short period of time.
“Any slackening during the festive period will lead to an increase in transmission and an increase in prevalence, potentially to a large extent,” the document said.
They later add: “SARS-Cov-19 has demonstrated high secondary attack rates in households (with estimates of up to 50% in a household infected with an infected member). The prevalence could easily double for a few days of the holiday season, with further multiplicative increases as new infections return to their “routine” networks. “
The warning comes as the government and Sage revealed the R-number for England in particular, and the UK as a whole, was now 0.9-1.0 for the first time since August. Due to the time lag in the data, Sage says this figure captures some of the impact of the latest England lockdown, but not its full effect.
The overall R number masks considerable variation around the UK. While R was found to be between 0.7 and 0.9 in the North West of England, it was 1.0 to 1.2 in the South East, suggesting that the epidemic decreased in the first and remained stable or increasing in the second.
But as signs grow that the lockdown begins to impact infection rates and hospital admissions, it could be a few weeks before such changes are reflected in the daily number of deaths. As of Friday, 521 people in the UK are believed to have died from Covid.
Boris Johnson announced Tuesday that three households would be allowed to mix for up to five days at Christmas, forming a “bubble”. However, Sage experts reveal in the files that Christmas bubbles will always be risky.
“If all households formed a bubble with another household, the number of out-of-bubble contacts should be reduced to the levels observed in April 2020 (
Experts also warn that while it is better to form bubbles rather than limit contacts to a specific number, it is essential that people stick to a single bubble.
“Allowing people to form different bubbles over the holiday season would be worse than limiting them to a single bubble,” the modeling team said.
Sage experts believe that a key factor in reducing the impact of Christmas socialization is to minimize the prevalence before the festivities – not only to reduce the chances of meeting an infected person, but because an increase in infections if the prevalence is already high is likely to have a greater impact on hospitalizations and deaths.
“Households can significantly reduce their risk of introducing an infection into an event by quarantining themselves for two weeks,” they say. “However, this raises issues of fairness, as many families would struggle to do this, including frontline workers.”
The documents also shed light on the delay given by the government for the Christmas mix. “Bubbling would be more effective if it was limited in time to less than one generation of infection (about a week)”, write the modeling experts. Professor Liam Smeeth, professor of clinical epidemiology at the London School of Hygiene & Tropical Medicine, said: “A period of multi-level measurements in December is now warranted in order to allow for some social mixing over Christmas which is so important for many. I suspect that another breaker in January or maybe February may well be needed as Christmas will put such upward pressure on transmission rates.