OPINION | Our best hope to fight coronavirus

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Editor's Note: Jeffrey Sachs is a professor and director of the Center for Sustainable Development at Columbia University. The opinions expressed in this comment are those of the author; See more opinion articles on CNN.

(CNN) - Covid-19 is a pandemic of remarkable ferocity. The world population lacks immunity because this is the first time in known history that we have faced this coronavirus. The virus is also highly transmissible.

To add to the problem, many people who have been infected experience mild symptoms, if any, and transmit the disease without realizing the infected person or those whom they are infecting. The consequences of infection are often severe: approximately 14% of cases require oxygen therapy and 5% require admission to an intensive care unit. A study by researchers at Imperial College London, which applied Chinese data to the United Kingdom, estimates that the overall death rate is around 0.9%.

There are various phases in a pandemic. When there are still a few cases, it is still possible to identify and isolate infected individuals and track people they have come into contact with so that they can also be tested, monitored and, if necessary, isolated. This is the so-called test and trace phase. Some places in East Asia, especially Singapore, Hong Kong, and Taiwan, have so far managed to limit the epidemic mainly to the testing and tracking phase.

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When testing and tracking are lax, as it has been in the United States since January, the epidemic enters a second phase that involves the spread of the community and the exponential growth of cases. The growth rate of covid-19 is extremely fast, with a doubling time of five days or possibly less in an uncontrolled epidemic. A 5-day doubling rate would mean 6 doublings in one month and 12 in two months, or roughly a 4,000-fold increase in infections in two months. The increase in infections and deaths would occur much more quickly with an even shorter doubling time. The United States is now in this explosive stage.

The key to limiting the epidemic in this breakdown phase is some form of closure in which all nonessential businesses are closed; events are canceled; public areas are cleaned; and most people are ordered to remain in their homes. China implemented a strict blockade several weeks after the epidemic; Italy introduced its own measure last week. California, New York and now many other states have issued "stay home" orders asking people to just go out for activities like buying food. While President Donald Trump has so far ruled out talking about a national blockade policy, some experts consider it inevitable.

A successful closure lowers the rate of spread and, if carried out early enough and effectively, prevents the healthcare system from being completely overwhelmed, a frightening prospect that could result in the unnecessary death of thousands of thousands of patients from covid-19, along with others who need immediate medical attention. Furthermore, it can ultimately tilt the curve downward, dramatically reducing the number of people currently infected, as has been achieved in China.

But any stage of closure is extremely costly socially, politically, and economically, and the goal is to lift it as soon as possible to avoid a rebound in the epidemic. The goal is to reduce the number of cases to make it feasible to go to a large-scale testing and tracking phase through a highly amplified public health surveillance system. Longer-term solutions could include new drugs and vaccines, and the gradual build-up over years or decades of collective immunity.

According to standard epidemiological models, an uncontrolled epidemic could infect 60% of the population, which means around 200 million Americans. With a death rate of the order of 0.9 percent, that could mean 1-2 million deaths. The prospect is so dire that every effort must be made to break the transmission through a lockup.

The United States is still in the disastrous phase of rupture, as a result of the surprising incompetence of Trump and his administration. Trump did not take this pandemic seriously at first and made his way through the first phase of the epidemic when the newly introduced virus was still potentially controllable through testing, tracking, and associated public health management. His narcissism, incompetence, and hesitation have seriously endangered the nation. There will be enough time to dispense political justice to Trump. Now we must act to save our country.

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Most urgently, the United States must now block much of our national economic and social activity to slow down and then substantially break transmission of the virus. National production will plummet from April to June, perhaps by more than 20 percent.

Never before has our national policy been the deliberate closure of much of the economy, but that is what we need now to survive. We must continue to run the essential parts of the economy (most government services, healthcare, food supply chain, social support, infrastructure, urgent maintenance) and online services (finance, media, services professionals, e-commerce). Some work tasks (thank God, farming between them) are also relatively safe, since they do not involve close interpersonal contacts that can transmit the virus.

In the closure phase, we must provide special protection to the older population (60+) and to the population with previous conditions (eg, cardiac, pulmonary and metabolic disorders). Those over 60 account for 80% of deaths. Older people will need special social support to stay healthy in isolation. We must also support society to deal with the mental and physical dangers of prolonged isolation. Additionally, we must provide urgent income support, especially unemployment compensation and help for low-income and indigent families.

Another obvious need is to ensure that there are enough ventilators, hospital beds, and protective gear so that healthcare professionals can cope with the surge in patients in the coming weeks. It is inconceivable and unacceptable that nurses, doctors, and assistants are fighting on the front line without masks and other critical equipment. There is no time to lose.

During the closure phase, we must develop the capacity of our health system to assess and track disease. This capacity is currently lost, largely due to the incompetence of the Trump administration. Once this period reduces the prevalence of infection, we will want to move to testing and tracking as soon as possible, giving us the opportunity to lift closures step by step. In essence, we will move from a costly and widespread blockade to a more focused control of the epidemic in public health. This will only be possible under two conditions: a substantial reduction in the incidence of new infections and a much greater ability to test, track and isolate infected people.

China and other East Asian countries are showing us how to overcome the fugitive epidemic and keep infections under control through testing and tracking. Due to Trump's hesitation, we missed the opportunity to do this at first, but now we must plan for this type of control in the coming months. This time the United States must learn from others. Global cooperation and the exchange of best practices is our best hope to emerge from this crisis alive and intact.

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