A few months in, it is still hard to grasp the scale and scope of COVID-19’s global impact. A third of the world population is under some sort of “lockdown.” Over 200 countries are affected, and the number of new cases and deaths in many places are still growing exponentially. All the while, a second crisis, in the form of an economic recession, is underway.

We all want to leave this crisis behind as soon as possible. But as eager as we are to restart social and economic life, to do so, we must give prime focus on public health. That comes with an enormous cost, but it is better than the alternative. Government and business collaborating, based on the latest scientific evidence are our best chance at preventing a hopefully short-term recession from becoming a global depression.

While governments and companies who have “bent the curve” can cautiously start initiatives to gets parts of social and economic life going again, always monitored by public health officials, companies should leave their competitive interests temporarily behind, and work together to ensures that the most effective vaccine can be determined as fast as possible, and the necessary production can start on a large scale as fast as possible. It is the only true way out of this crisis.

Let us start by acknowledging what is known medically today. While we don’t know the full facts on COVID-19 yet, it is clear will pose an exceptional risk to global public health for at least another year and possibly much longer, because of three crucial reasons. First, this novel coronavirus is extremely infectious. Second, the COVID-19 disease it causes is very severe. And third – and this is crucial – we have no “background” immunity in the population and don’t have a vaccine yet.

Consider first its infectiousness. Anyone infected with this new virus infects on average between two and three other people and nobody has immunity against this brand-new virus. Within a few weeks, this virus has infected millions (the official case count is still under 2 million, but the unofficial one is likely a least five times as high and counting). And in the next few months, COVID-19 imperils most of the global population.

That means we are facing a full-scale pandemic, and there is no shortcut out of it. This virus in the past 100 years is only comparable with the Spanish flu of 1918, that over two years killed approximately 50 million people and was followed by a 1920-1921 economic depression. That flu was a very virulent and infectious virus as well, to which the world population had no immunity at all. If that disaster repeats itself, we’re facing the prospect of many millions of deaths and a prolonged depression.

Second, we now know that the death rate of confirmed COVID-19 cases is in the order of 5 percent. The mortality rate in all cases (including the as yet unrecognized) is still unknown, but it is most likely at least 1 percent. Such percentages are very serious: they are at least 10 to 50 times higher than for the seasonal Influenza, and comparable to the infamous “Spanish Flu.” All epidemiological parameters (infectiousness, virulence and lack of immunity) are similar between the Spanish flu and COVID-19.

As a consequence, hospitals around the world are now flooded with patients. From New York to Tokyo, and from Barcelona to Tehran, thousands are already dying every day, in what can only be described as a very exceptional global health emergency: all “frontline” health care workers around the globe testify that they have never seen this.

And third, and this is the most problematic fact: there is no vaccine, and not even a very effective treatment. A flu vaccine is useless against COVID, as are most other existing drugs that have been tested. Reports on (partial) efficacy of the chloroquine or anti-HIV drugs have to be confirmed. That leaves us, with the outlook of continued infections and death until at least the end of 2020.

If this wasn’t enough of a dramatic outlook, consider that the impact of the virus has so far been felt mostly in the developed world, the “Global North.” The final death toll and much of its socio-economic impacts, however, will be determined by its spread and mortality rate in the low- and middle-income countries, in the “Global South”, which count several billions of people who are as of now still only at the start of the pandemic.

A hopeful sign is there that the population is much younger and less affected with the cardiovascular and other co-morbidities (which increase the risk on severe disease in the North). But, people in the South have a much higher burden of “background” infections and less access to enough quality food and medical services. What happens in the poor “inner city” areas of New York City is probably partly predictive of what will happen soon in the Global South, and that picture looks rather bleak.

Knowing all this, which social, economic and public health scenarios should we reasonably plan for, and what is the solution?

In the absence of a vaccine, this pandemic will only stop when a large part of the population acquires immunity after infection. It is the famous concept of “herd immunity.”

You could argue (as the U.K. did for a while) that we should let that happen, the sooner the better. The problem with that strategy is what we witness today in New York City: before this herd immunity is installed, you have a very rapid exponential “natural spread.” So many people get sick simultaneously, desperately in need for medical care, that the health system crashes and many (hundreds of) thousands of people will simply suffocate, exacerbating social and political tensions.

We are better off then, maintaining to various degrees the present measures of containment: not to kill the virus or to end the epidemic very soon, because that is impossible without a vaccine. But to slow the epidemic down sufficiently to give our health systems the chance to cope: support patients that have serious breathing problems with oxygen and artificial ventilation to give their immune system the chance to overcome the infection. We may get to herd immunity, but only very gradually.

Looking forward, the big question we are left to answer is this: how long should the lockdown be maintained and when and how do we release it gradually?

In the end, we must enable the economy to restart, and prevent a second epidemic of mental health or social problems, while avoiding a new surge in the epidemic. China, Korea, Germany and Austria are already cautiously re-starting or planning to re-start parts of societal and economic life. But they must to do so in an extremely cautious manner, led by public health experts. Failing to do so could trigger financial and mental health problems comparable in impact to a public health crisis.

Two complementary strategies to prevent further epidemic growth can be rolled out, which enable various governments to take decisions on how to gradually restart social life:

The first is serological testing, i.e. looking for COVID-specific antibodies in the general population. By doing this, you can monitor what fraction of the population has been in contact with the virus and is potentially immune.

The second is to develop a reliable “rapid antigen tests” to quickly diagnose those who carry the virus (without or with minimal symptoms) and install “contact tracing” by app-technology to rapidly identify contacts of the infected persons that could be quarantined to prevent further spreading.

For governments and businesses, combining both strategies may be their best chance of getting the economy going again. Which aspects they start first, between opening schools, workplaces, shops and restaurants, should be a country-by-country choice. But once best practices become clear, countries should be willing to learn and coordinate with each other. We will only be able to get out of this crisis together. If we fail to help each other, we risk a serious relapse, making the recipe for a crisis turned depression.

Ultimately it should be clear: the only long-term strategy to eradicate this virus is a COVID drug and/or vaccine. This type of development supposes that one has at least a few dozens of candidates that work very well in vitro and in animal models. And then it usually takes several years to bring one or two to the market. Given this knowledge, we shouldn’t plan for an economic and social recovery in a year, simply out of hope.

Of course, we could be lucky that an existing, already approved drug could also act against this virus, or that an efficacious COVID drug could prevent mortality and promote recovery of infected subjects. On the former, mass screening is happening today, so we will know soon. Also new schemes for rapid testing of candidate vaccines are set up and a suitable candidate could emerge within months. But even then, it will take time to produce and deliver it on a world-wide scale. Nevertheless, all global stakeholders should provide all their support, financially as well as through bureaucratic means, to get to this solution as fast as possible. This is a time for collaboration, not competition.

In the absence of a widely available vaccine, and knowing this will likely take more than a year, and possibly multiple years, not a couple of months, we must make fundamental changes to our economic system. To prevent an economic collapse, governments will need to take on large and unprecedented roles in securing business continuity and jobs. The public debt that will go hand in hand with, will need to be carried by the strongest shoulders – the companies and individuals most able to take it on. The crucial principle, that everyone will need to subscribe to, is that we’re all in this together, for the long haul, and we must all come out of it together.

We have faced grave crises before. But if we want to come out of this unscathed in the long run, we must plan for unprecedented impact and collaboration in the short run. We’ll overcome this crisis, but only if we work together and dig in.

This article is part of a special series on how the coronavirus is changing our lives, with insights and advice from the TIME 100 community. Want more? Sign up for access to TIME 100 Talks, our virtual event series, featuring live conversations with influential newsmakers.

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