The prime minister says Britain will follow its own path on the coronavirus outbreak, one that takes a one- to two-year timeframe, and assumes that everyone will eventually be exposed to Covid-19.

As a global health governance expert who has been following this outbreak since December along with colleagues and the World Health Organization (WHO), we have learned how much countries can do, at an early stage, to stop this virus spreading rampantly throughout society. In fact, there are early signs of success from Taiwan, South Korea, Singapore, Hong Kong and China on how acting before case numbers increase rapidly can “flatten” the epidemiological curve and the number of daily new infections.

Yet scientists and medical experts such as Richard Horton, the editor of the Lancet, have expressed alarm at being taken down a new path without any transparency around the evidence being used to inform these decisions, or any public discussion around the models and their assumptions.

Quick Guide What to do if you have coronavirus symptoms in the UK Show Symptoms are defined by the NHS as either: a high temperature - you feel hot to touch on your chest or back

a new continuous cough - this means you've started coughing repeatedly NHS advice is that anyone with symptoms should stay at home for at least 7 days.

If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home. After 14 days, anyone you live with who does not have symptoms can return to their normal routine. But, if anyone in your home gets symptoms, they should stay at home for 7 days from the day their symptoms start. Even if it means they're at home for longer than 14 days. If you live with someone who is 70 or over, has a long-term condition, is pregnant or has a weakened immune system, try to find somewhere else for them to stay for 14 days. If you have to stay at home together, try to keep away from each other as much as possible. After 7 days, if you no longer have a high temperature you can return to your normal routine. If you still have a high temperature, stay at home until your temperature returns to normal. If you still have a cough after 7 days, but your temperature is normal, you do not need to continue staying at home. A cough can last for several weeks after the infection has gone.

Staying at home means you should: not go to work, school or public areas

not use public transport or taxis

not have visitors, such as friends and family, in your home

not go out to buy food or collect medicine – order them by phone or online, or ask someone else to drop them off at your home You can use your garden, if you have one. You can also leave the house to exercise – but stay at least 2 metres away from other people. If you have symptoms of coronavirus, use the NHS 111 coronavirus service to find out what to do. Source: NHS England on 23 March 2020

Predictive models are useful, but they depend on the parameters that are input. In this case, I can only presume these include: that this will be a seasonal virus; that no vaccine will be available soon; that largely over-70s will be affected badly; that viral mutation is unlikely; and that reinfection is not possible. We do not yet know the exact assumptions given they have yet to be shared by the government; but if these are some of them, the evidence is not clear. For example, early data from Italy shows that 12% of intensive care unit (ICU) patients are between ages 19 and 50, and 52% are between 51 and 70.

Many British people are now looking to other countries and wondering why our government is taking such a different path, given those other nations must also have their own modellers and experts. And NHS staff don’t understand why pressure is not being immediately taken off the health sector, to give time to build capacity. Now is the time for decisive action, especially given that we still are learning about the virus. Based on the experience of other countries and in previous outbreaks, there are three clear steps we can take.

NHS staff themselves don’t understand why pressure is not being immediately taken off the health sector, to give time to build capacity

First, resume testing – starting with health staff and first-line responders, and eventually others around the country – to understand where exactly the virus is, how many people have been infected, and how to break chains of transmission. Health staff on Covid-19 wards need to know if they have the virus – not only so they can protect their families, but also so they don’t go on to expose others in the hospital. We need to avoid clusters of cases among vulnerable groups there, which is what occurred early in Italy’s outbreak.

The WHO director-general, Tedros Adhanom Ghebreyesus, has said we need to “test, test, test”. South Korea, widely seen as a success, is doing 10,000 tests a day and its foreign minister has said: “Testing is central because it leads to every detection. It minimises further spread and it quickly treats those with the virus and that’s the key behind our very low fatality rate.” If capacity is a problem within the UK, then the government needs to communicate a clear plan of how many tests can currently be conducted, who will be prioritised and why, and what the plane is for scale-up.

Second, we need to be protecting our frontline health workers by ensuring they have adequate personal protective gear in line with WHO guidance, and that they are not being pressured to see patients when it could be a risk to them. The US vice-president, Mike Pence, says the federal government will now prioritise health workers and frontline responders. Yet within the NHS, shortages of masks, gowns and gloves have meant that many health workers feel exposed, and anxiety is growing. A clear statement from the government that this will be prioritised is important, as our health workforce is limited, precious and cannot be manufactured in a day or weeks.

Third, we need to buy time for the NHS to acquire more ventilators, set up sufficient beds and get in the other equipment that will be needed in the coming days and weeks. Data from Italy and China indicates how fast the disease will spread, and how social distancing measures – such as asking people to work from home, stopping nonessential travel and banning large gatherings – can slow it, and reduce the number of patients who require hospitalisation and ICU care.

Speed is of the essence. As Mike Ryan, the head of health emergencies at the WHO, has said: “Have no regrets. Be the first mover. The virus will get you if you don’t move quickly … if you need to be right before you move, you will never win.” There is generally consensus that, while disruptive both economically and socially, short-term social distancing is effective at slowing transmission. The debate is what happens when these restrictions are lifted and how sustainable “shutting down” society is. But right now, what we need is time. Time for the NHS to prepare, for rapid diagnostics, for vaccine trials to be conducted and for antiviral therapies to be trialled.

Right now there is confusion among the public about how serious this crisis is; whether the media are overhyping it; and who to trust, given different governments are taking different strategies. Many individuals and institutions are making their own decisions based on what they are hearing from friends and colleagues from around the world. At this time I hope the UK government will be transparent about its decision-making; willing to listen to NHS staff concerns; humble in learning from other countries’ experiences; and pro-active in building relationships with them. We will need this to get us through the coming months with the fewest deaths and the least suffering possible.

• Devi Sridhar is a professor and the chair of global public health at the University of Edinburgh