BLOG: The United States should look to Liverpool as a model for frequent rapid Covid testing
5 min read
Now Joe Biden has been sworn in as the 46th President of the United States, there is much scrutiny on how he deals with the Covid crisis which has now claimed its 400,000 US victim.
In this letter from America, Harvard School of Public Health Professor Michael J Mina explains why he has been watching the Covid smart testing programme in Liverpool with growing interest, and believes the new US administration should use the model to help it tackle coronavirus.
Nearly one year into the global pandemic, despite the acceleration of several promising vaccines, COVID-19 is still spreading, including at uncontrolled levels in the United States.
Importantly, frequent, accessible rapid antigen testing can serve as a backstop in the event that new variants of the SARS-CoV-2 virus learn to evade the immune system’s responses to vaccines, as we are currently seeing with the 501Y.V2 variant.
Last autumn, Liverpool launched an ambitious pilot programme that utilized frequent rapid antigen testing, and the programme’s success is a model for the UK and the world. The city used rapid antigen testing to test people frequently and give them immediate results, which identified asymptomatic, infectious individuals before they could infect others.
We have learned with COVID-19 that individuals transmit when their viral loads reach high amounts, usually three to five days after an exposure and crucially usually two days before symptoms arise. Rapid antigen tests register the virus regardless of symptoms, as soon as the virus grows to viral loads that could be potentially transmissible, making this a powerful tool to identify cases before the virus spreads.
Frequent testing of a large fraction of a community – like what is currently happening in Liverpool and soon across the entire UK – can induce vaccine-like herd effects.
Our research has shown that testing just half of a community once or twice per week, with rapid return of results, can detect enough infected people early enough in their transmission window to stop them from spreading, on average, to more than one individual.
Like a vaccine given to half of a community to induce herd immunity by blocking onward transmission, frequent rapid testing also blocks onward transmission, and can bring the reproduction of the virus (“R”) to below one in weeks.
The best way to think about how this can work is to consider 100 infected people. Currently, 100 infected people will go on to infect about 140 additional people. This means that 100 infected people will become approximately 500 new infections over a period of 3-4 weeks. With frequent rapid testing on the other hand, if enough people test themselves frequently enough such that those 100 people go on to infect 90 people (not nearly a perfect program), then in 3-4 weeks those 100 infected people become only approximately 20 infected people. That’s right, the programme does not need to be perfect. The frequent rapid testing programme just needs to include enough people such that 100 people go on to infect 90 people and in a matter of weeks we will have just 20 new infections instead of 500 – a 96% reduction in new cases!
I commend Liverpool and the UK government for listening to the scientific community, understanding this critical principle of epidemiology, and taking bold action to make frequent rapid testing one of their key weapons against COVID-19.
As Liverpudlians know, frequent rapid testing doesn’t only curb the spread of COVID-19; it also helps to regain a sense of normalcy in our lives.
For example, the results of Liverpool’s first pilot programme were so successful that the city was able to re-open critical parts of the economy again right before the Christmas holiday. This included the safe reopening of the hospitality and leisure job sectors, which employs 50,000 people and is worth £5 billion to the Liverpool economy. Liverpool educated residents about the importance of frequent testing, using a “test before you go” campaign to encourage people to get tested before they did their Christmas shopping or went to a football match.
As someone who has been advocating for this type of frequent rapid testing, I’ve been fascinated watching the Liverpool programme in action. In the first week of January, more than 36,500 Liverpool residents got tested, which was a regional record.
People are building the process of getting tested into their daily lives. They understand the value. They want to do their part to keep their loved ones safe. The city has also done a good job with expanding testing sites throughout the community so that residents don’t have to go out of their way to get tested. We need testing to be as accessible as possible for a frequent rapid testing programme to work.
Liverpool’s experience is yet another reason why frequent rapid testing should be embraced by the United States and other countries around the world. As an informal advisor to my country’s policymakers, I am encouraging them to look at Liverpool’s success story and learn from the city’s best practices and lessons.
This pandemic has ravaged local economies and created so much hardship. By making frequent testing with rapid results available to all citizens, especially in homes, schools, workplaces, retail shops and restaurants, entertainment venues and long-term care facilities, the economy can reopen safely and we can quickly stop the spread of COVID-19. 11 months into the pandemic, we should be trying everything we can to stop it – and Liverpool’s example is a good one to follow.
Michael Mina, MD, PhD, is an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health and a core member of the School’s Center for Communicable Disease Dynamics (CCDD). He is additionally an assistant professor in immunology and infectious diseases at the Harvard Chan School and associate medical director in clinical microbiology (molecular diagnostics) in the Department of Pathology at Brigham and Women’s Hospital, Harvard Medical School. Follow Dr. Mina on Twitter at @michaelmina_lab.