Imperial College London

Coronavirus infections continue to grow exponentially in England - REACT study

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A home coronavirus testing kit

The number of people testing positive for the coronavirus in England is continuing to rise rapidly, recently doubling every six days.

According to new REACT study data, based on home swab tests taken by over 47,000 people between 24 June and 5 July, around 1 in 170 people had the virus during this period, or 0.59% of the population. This is four times higher than the study’s previous report when 0.15% of people were infected, or 1 in 670, as of 7 June.

"It is encouraging to see lower infection prevalence in people who have had both doses of a vaccine." Prof Paul Elliott School of Public Health

These interim findings from Imperial College London show that the prevalence of infection has risen substantially in all age groups under 75. The biggest rise was seen in secondary school-aged children (aged 13-17) where infections were eight times higher than previous findings, with around 1 in 70 infected.

The epidemic has grown in all parts of the country but most notably in London, where infections rose by eight-fold. Although rates of infection were three times lower in fully vaccinated people under the age of 65 compared to unvaccinated people, both of these groups saw a similar proportionate rise in infections.

Professor Paul Elliott, director of the REACT programme from Imperial’s School of Public Health, said: “In spite of the successful rollout of the vaccination programme, we are still seeing rapid growth in infections, especially among younger people. However, it is encouraging to see lower infection prevalence in people who have had both doses of a vaccine. It is therefore essential that as many people as possible take up both vaccine doses when offered.”

These interim findings from the ongoing REal-time Assessment of Community Transmission (REACT-1) programme, led by Imperial and carried out in partnership with Ipsos MORI, are available here in an interim pre-print report and will be submitted for peer-review. The final report from this current testing round will be available later this month.

Rising infections among vaccinated people

For this latest round of the ongoing REACT study, 47,729 people have so far swabbed themselves at home and their samples were analysed by PCR testing. 237 of these were positive.

"Vaccinated people still have a risk of becoming ill from the virus and infecting others." Prof Steven Riley School of Public Health

Between the previous testing round and these recent swabs, infections were doubling every 16 days. But during the recent round only there was an acceleration in growth, with infections doubling every 6 days and a corresponding reproduction number (R) of 1.87.

The highest prevalence was found in 13-17-year-olds at 1.33%, up from 0.16% in the previous testing round, and 18-24-year-olds at 1.40%, up from 0.36%. Infections were lowest in people aged 75+ at 0.13%, however this is nearly double the previous round when 0.07% were infected.

By vaccination status, people under the age of 65 who were unvaccinated had an infection rate more than three times higher than those who were double vaccinated (1.15% vs 0.35%). However in both groups, infections were four to five times higher than the previous round. For those 65 and over who had had two doses, infections remained low but grew four-fold compared to the last testing round (0.06% to 0.24%).

Professor Steven Riley, Professor of Infectious Disease Dynamics at Imperial, said: “Although the vaccines offer good protection against infection and severe disease, vaccinated people still have a risk of becoming ill from the virus and infecting others. That’s why it’s really important that we get as close as possible to 100% of people taking two doses of the vaccine.”

Sharp growth in London

Across the country London had the highest rate of infections at 1.08%, up from 0.13%, followed by Yorkshire and the Humber at 0.78%, up from 0.17%. The South East and South West had the lowest rates at 0.34% and 0.35% respectively.

"It is more important than ever to get that life-saving second jab so we can continue to weaken the link between cases, hospitalisations and deaths." Sajid Javid Health and Social Care Secretary

Health and Social Care Secretary Sajid Javid said: “As we unlock society and learn to live with COVID-19, we will inevitably see cases rise significantly over coming weeks. But today’s findings show that infection rates are three times lower for those who have had two vaccine doses.

“It is more important than ever to get that life-saving second jab so we can continue to weaken the link between cases, hospitalisations and deaths and build a wall of defence against the virus.

“As we move from regulations to guidance and get back to our everyday lives, see our loved ones and return to work, it is vital people practice good sense and take personal responsibility for their own health and those around them.”

Monitoring the COVID-19 epidemic

The REACT-1 study is tracking current coronavirus infections in the community by testing more than 100,000 randomly selected people each month over roughly a two-week period. The study recruits new people each month to help ensure the sample represents the wider population and offers a high-resolution snapshot of the situation across a particular time period.

“It is hugely encouraging to see the vaccination rollout is having a significant impact on the spread of the virus." Nadhim Zahawe COVID-19 Vaccine Deployment Minister

This is different from the ONS COVID-19 Infection Survey which runs continuously and samples the same people over time to understand household transmission. Because the studies use different methods, this means that sometimes they report different figures.

COVID-19 Vaccine Deployment Minister Nadhim Zahawi said: “It is hugely encouraging to see the vaccination rollout is having a significant impact on the spread of the virus, however increases across all age groups highlight that even those who are fully vaccinated can end up sick in hospital.

“Almost two-thirds of adults – 64% – have had both doses of a vaccine, and so have got the maximum protection on offer.

“I urge everyone to get their first and second dose when invited, as every jab helps to curb transmission and serious illness, and for those who are double jabbed to continue to get tested if they have symptoms.”


Download the report here

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Justine Alford

Justine Alford
Institute of Global Health Innovation

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Tel: +44 (0)20 7594 1484
Email: j.alford@imperial.ac.uk

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