A team of British scientists published a worrying study on Wednesday of the new variant of coronavirus sweeping the UK. They warned that the variant was so contagious that new control measures, including closing schools and universities, may be required. Even that might not be enough, they said, saying, “It may be necessary to speed up the introduction of vaccines significantly.”
Nicholas Davies, lead author of the study, said the model should also serve as a warning to other countries where the variant may have already spread.
“The preliminary results are pretty convincing that faster vaccination is going to be a really important matter for any country dealing with this or similar variants,” said Dr. Davies, an epidemiologist at the London School of Hygiene and Tropical Medicine, in an interview.
The study, published by the Center for Mathematical Modeling of Infectious Diseases at the London School of Hygiene and Tropical Medicine, has not yet been reviewed by a scientific journal. The study compares a number of models as predictors of data on infection, hospital stays, and other variables. Other researchers are testing the variant in laboratory experiments to see if it is biologically different.
The study found no evidence that the variant was more deadly than others. However, the researchers estimated that it was 56 percent more contagious. On Monday the British government released an initial estimate of 70 percent.
Bill Hanage, an epidemiologist at Harvard TH Chan School of Public Health who was not involved in the study, said it provided a compelling explanation of the variant’s past and possible future.
“The overall message is solid and in line with what we’ve seen from other sources of information,” he said in an interview. “Is that important? Yes. Is there any evidence of increased transmission? Yes. Will that have an impact in the next few months? Yes. These are all pretty solid. “
The variant, which British researchers became aware of earlier this month, has spread rapidly in London and eastern England. It contains 23 mutations, some of which can be more contagious.
Dr. Davies and colleagues found more evidence that the variant actually spreads faster than others. For example, they ruled out the possibility that it was becoming more common in some regions of the UK because people in those places were more moving and more likely to come into contact with one another. Data recorded by Google showing the movements of individual cell phone users over time showed no such difference.
The researchers built various mathematical models and tested each one as an explanation for the spread of the variant. They analyzed which model of spread best predicted the number of actually confirmed new cases, as well as hospitalizations and deaths.
The researchers concluded that the variant can, on average, spread to more people than other variants. Dr. Davies warned that their estimate of 56 percent more contagious is still crude as they are still collecting data on the recent spread of the variant. “I think if we get more of that corner we will be safer,” he said.
Despite the data he and his colleagues have so far, he is confident that the new variant must be taken very seriously. “I think that given all the evidence, it is a strong case,” he said.
Apr. 26, 2020 at 6:29 am ET
Dr. Davies and his colleagues then predicted what the new variant would do over the next six months and built models that took different constraints into account. Without a broader roll-out of vaccines, they warned, “Cases, hospitalizations, ICU admissions and deaths in 2021 could exceed those in 2020.”
Closing schools through February could buy the UK some time, the researchers noted, but lifting those additional restrictions would then result in a significant recovery in cases.
Dr. Davies and his colleagues also considered the protection vaccines offer. Vaccine experts are confident that coronavirus vaccines can block the new variant, although this needs to be confirmed by laboratory experiments that are currently being carried out.
To study the effects of the current vaccination rate, the researchers created a model that vaccinated 200,000 people each week. This pace was too slow to have much of an impact on the outbreak. “That kind of pace wouldn’t really help loosen control measures,” said Dr. Davies.
When they increased the vaccinations to 2 million a week, they saw a decrease in the peak load for intensive care units. Whether the UK can increase vaccinations by a factor of 10 is unknown.
As of Tuesday, the variant had not been identified in the United States, according to the Centers for Disease Control and Prevention. “Given the low proportion of US infections sequenced, the variant could already be in the US without being detected,” they warned.
The United States is vaccinating its citizens more slowly than expected. This could potentially become a problem if the variant spreads in the UK to the US.
“You need to be able to remove any obstacles to transmission as quickly as possible,” said Dr. Hanage.
Dr. Davies warned that the model he and his colleagues analyzed, like any model, was based on a number of assumptions, some of which could prove to be incorrect. For example, the rate at which infected people die from Covid-19 may continue to decline as doctors improve care for hospital patients. There are still uncertainties as to whether and by how much the new variant is more contagious in children.
They also didn’t consider other tools to stop the spread of the variant, such as an aggressive program to test people and isolate those infected. “That’s a limitation of the paper,” said Dr. Davies. Researchers are now starting to analyze new possibilities like this.
Nevertheless, Dr. Davies and his colleagues in the conclusion of their study: “There is an urgent need to examine which new approaches may be necessary in order to sufficiently reduce the ongoing transmission of SARS-CoV-2.”
Commenting on the new estimates, Alessandro Vespignani, director of the Network Science Institute at Northeastern University in Boston, who was not involved in the study, said: “Unfortunately, this is another turn in the plot.”
“While we were all excited about the vaccine,” he added, “there is a potential for a change in the epidemiological context that will make our next few months much more complex and dangerous to navigate.” Evidence is mounting that the variant is more transmissible, and this implies that even greater efforts are likely to be needed to keep its spread under control. “
Dr. Hanage warned that the model had some flaws. The researchers assumed that anyone under the age of 20 had a 50 percent chance of spreading the disease. Although this might be true for younger children, Dr. Hanage, it’s not for teenagers. “That’s the weakest part of their model,” he said.
Nevertheless, the study offers an important insight into the possible future of the country. “It’s not a forecast, it’s not a prediction, it doesn’t mean this is going to happen,” he said. “They say that if you don’t take it seriously, it can happen very easily.”
Benjamin Mueller contributed to the reporting.
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