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Hospital Healthcare Europe

Latest REACT-1 data reveal four-fold increase in COVID-19 infections

Rod Tucker
12 July, 2021  

The latest REACT-1 findings show a rise in COVID-19 infections across all age demographics highlighting the need for continued surveillance.

The REal-time Assessment of Community Transmission-1 (REACT-1) collects throat and nose swabs from a random and representative sample of the population aged 5 years and over, to identify trends in COVID-19 infections. These individuals are sent a self-administered throat and nose swab as well as a short self-completion questionnaire. The study has been collecting data since May 2020 and has a collection time-frame of approximately 3 weeks. The latest data is from round 13 and covers the period from 24 June 2021 to 5 July 2021.


From a sample of 47,729 swabs, there were 237 positive COVID-19 infections, giving a prevalence of 0.59% (95% CL 0.51 – 0.68%). The data represents an approximately 4-fold increase from the estimated prevalence found in round 12 of 0.15%. This estimate of the prevalence is similar to the results obtained in round 5 (18 September to 5 October 2020) but the rate of increase appears to be steeper. The authors of the report suggest that there is a doubling time for infections of 6.1 days, making the so-called R number 1.87.

The REACT-1 study provides a breakdown of the prevalence for gender, age groups, ethnicity and household size and indicate an increase in COVID-19 infections across all demographics. Interestingly, the latest data show that the positivity swab rate is higher in men (0.71%) than women (0.47%). The prevalence is also rising among all age groups. For example, the biggest increases have occurred in those aged 13 to 17 years, at 1.33% (up from 0.16%) and among those aged 18 to 24 years, at 1.40% (an increase from 0.36%). However, the prevalence among those aged 5 to 12 years has increased from 0.35% in round 12 to 1.05%. While an increasing number of people have now been fully vaccinated, there has still been more than a 3-fold increase in those aged 65 to 74 years, 0.24%, up from 0.07%. It has also more than doubled (0.28% to 0.62%) in those of Asian ethnicity and increased more than four times (0.24% to 1.11%) in households with 5 people.

The REACT-1 data has also considered the positivity rate based on self-reported vaccination status. In those aged 65 years and over, the estimated positivity rate in fully vaccinated individuals has increased from 0.06% to 0.24%. Based on these results, the authors have estimated a vaccine efficacy of approximately 70%.

The authors are clear that the UK is experiencing what they describe as as a substantial third-wave of infections. This signal is also reflected in other data such as the latest infection survey from the Office for National Statistics, which has estimated that in England, for the week ending 26 June 2021, there were likely to be 211,100 people infected with COVID-19 or 1 in 260 of the population.

The REACT-1 study concludes on how the UK is entering a critical period, especially with the proposed relaxation of the need for social distancing and the wearing of face masks, which makes a strong case for the continued need of current surveillance programmes.

Source. REACT-1 round 13