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Imagine you are in a small boat far, far from shore. A surprise storm capsizes the boat and tosses you into the sea. You try to tame your panic, somehow find the boat’s flimsy but still floating life raft, and struggle into it. You catch your breath, look around, and try to think what to do next. Thinking clearly is hard to do after a near-drowning experience.

You do, though, realize two important things: First, the raft is saving your life for the moment and you need to stay in it until you have a better plan. Second, the raft is not a viable long-term option and you need to get to land.

In April 2020, the storm is the Covid-19 pandemic, the life raft is the combination of intense measures we are using to slow the spread of the virus, and dry land is the end to the pandemic.


The U.S. is still in the clambering-into-the-life-raft phase of responding to Covid-19, and thinking clearly about what to do is still difficult. This confusion has made it hard to appreciate two facts: One is that social distancing combined with scaling up testing, production of medical equipment, and other countermeasures are essential and must be replicated across the country, intensified, and continued. The other is that if these measures have the desired effect of reducing the number of new cases accumulating each day, they provide only a temporary solution.

We still need to find a way to bring the pandemic to a permanent conclusion.


Several countries in Asia controlled their epidemics before a majority of the population was infected. Some, like Taiwan and Singapore, did so by containing infections from the start. Others, like China and Korea, did so only after large outbreaks. The control they have reached is only a life raft, not dry land, because unless there have been extraordinarily high levels of infection that were so mild as to go unnoticed, most people in these countries remain susceptible to infection.

Viruses do not remember they were previously under control and will resurge when restrictions are lifted. Just look at what happened in 1918, when cities that had cracked down on the transmission of influenza lifted their restrictions and flu transmission rose again. Mathematical models of Covid-19 by our group and others that incorporate these lessons show that, in the short term, social distancing and other interventions can reduce the impact of the virus. But the same models show that when these interventions are eased, the problem returns.

Let’s be clear. With something like Covid-19 there is the first peak, and there’s the whole epidemic. For the first peak, the evidence so far points to a worrisome possibility of overwhelming our intensive care units — even with the degree of social distancing we’ve achieved — as we’re seeing in New York City. But every bit we slow and flatten the curve will make that less likely and less dramatic, if and when it happens.

It is very possible that after this first wave subsides, we will still have a largely susceptible population, though that depends on how well the social distancing works. Effective treatments and increased ICU capacity could reduce the demand for critical care, lightning the load on the health system, but again, these measures only delay things.

If the SARS-CoV-2 virus has a contagiousness of three, meaning every case infects three other people, then we won’t get to the end of the epidemic until two-thirds of the population has become immune by infection or by vaccination. Successful control of the first peak of infections could leave a majority (perhaps a large majority) of the U.S. population still susceptible to the virus.

There are several broad ideas for how to get to dry land, which is widespread immunity in the population. But each has enormous problems.

One way is to let up on social distancing soon and let the epidemic run its course. That would lead to many deaths and completely overwhelm health care systems around the country. Another way is to maintain intense social distancing until there is a vaccine — but the arrival of a vaccine is uncertain and, absent a miracle, will likely take more than a year. Meanwhile, society and the economy would suffer.

If the first wave really is controlled, another option would be to try multiple rounds of social distancing: instituting it to bring the epidemic under control then letting up, perhaps only in certain areas, to allow cases to occur and immunity to accumulate gradually in the population, and then again introducing another round of social distancing. Our model of this process shows that it would take multiple rounds and would be challenging to accomplish without errors that lead to ICU overload. It would also be difficult to maintain the political and social will to implement this.

The most ambitious approach would be to intensify social distancing and scale up testing until we have the ability to know about nearly every case of Covid-19, trace his or her contacts, and control the spread of the disease one case at a time. This, though, is hard to envision. Even though Singapore detected the infection early, Covid-19 has stretched the island’s public health system to the limits, and our public health system has not had the practice and the resources devoted to stopping a pandemic that Singapore has invested since it faced down severe acute respiratory syndrome (SARS) in 2003. And continued risk of imported cases of Covid-19 from elsewhere in the world — or even from other parts of the country — would lead us in this best-case scenario to restrict and intensively screen travelers for an extended period.

As epidemics and responses to them are local, the scenario in one part of the U.S. could differ from that in another. A report from the Institute for Disease Modeling suggests that even Seattle’s relatively prompt response may have only slowed the spread of the infection and it may see a single-peaked epidemic with much of the population infected, despite social distancing efforts. If accurate, recently reported fever data from a networked thermometer company that illness rates may be coming down, not just growing more slowly, then we may see a second peak once social distancing efforts are lifted.

Clearly, we need more testing to understand each region’s epidemic trajectory.

A vaccine is ultimately our best hope, but that is in the future — many months away, if not a year or more, in the rosiest scenarios.

Whatever path we choose — and it may be a mix of paths in different parts of the country, as the local epidemics and responses are so varying — we should be working overtime to make use of the time we buy with social distancing. That means:

  • Building capacity to control transmission by continued social distancing, massive testing, and meeting the needs of healthcare workers for personal protective equipment.
  • Investing in efforts to mitigate the impact of Covid-19 by rapidly finding treatments, increasing health care capacity, and further accelerating work on a vaccine.

Despite the near-drowning of hospitals and intensive care units we’ve observed in many countries, and may soon witness in the U.S., we must think clearly and understand that getting through the first phase of this pandemic only gets us into the life raft, not to dry land.

Marc Lipsitch is professor of epidemiology and director of the Center for Communicable Disease Dynamics at the Harvard T.H. Chan School of Public Health, where Yonatan Grad is an assistant professor of immunology and infectious diseases.

  • Thanks for writing this excellent piece that addresses one of my main concerns. What happens after all the high-profile coronavirous infection locations die down? Answer: It is not going away. Clearly, we are in this for a long haul. We need to pay more attention to this and, of course, the search for a vaccine. This is the kind of info that matters, from people who know what they are doing, and written in a way non-medical-professional people can get their arms around. The piece also lets me see what I need to be doing and planning for the foreseeable future.

  • If China allows wet markets to operate again, then the name WuBat virus likely does not apply, and very likely these markets are NOT the cause of that virus that’s ravaging the world. So then WHAT caused this pandemic? Is it lab-made? Is there indeed a Biological Warfare research facility in Wuhan? What can western satellites, spies, infiltrators do to either confirm or eliminate the growing notion about a modified virus from a (Wuhan) lab? Did the virus escape? Or is this an outdoor experiment that ran amok? I first laughed these notions away as garbage, but now I am not so sure anymore. China has the power to stop traditions deemed un-healthy or dangerous, and yet it allows wet-markets to open again. So what then is the source of this virus???

    • There is no evidence it was not the wet market, as I say, if they tested all animals and only one carries the virus, then removing that one should fix the problem. The politicians are probably being paid a lot of money to allow them, since it is known they should be banned. The animal rights people claim asian organized crime is involved.

  • I have a theory and question I keep asking in these Comments sections.
    There are reports the Chinese authorities have reopened the “wet markets” in China now – allowing sale of wild animals again.
    I am not sure what to make of this, and so I am asking virologists and epidemiologists what it could mean. Some possibilities come up:
    1. They know the source of the disease, and it really WAS a manmade virus from one of their labs, and it does not infect it’s original animal host any longer, therefore the wet market will not start a new epidemic.
    2. When they shut down Wuhan, they took samples of the animals in the wet markets found out it was only in one species, and have allowed the wet market to reopen, while very quietly forbidding trade in the one host species. This would be fairly safe for them to do, and, reopening the markets is of great propaganda value, because then they can plausibly deny it came from the markets in the first place.
    3. They have a vaccine and are confident it works, is safe, and they can get it to enough people soon enough to shut down any epidemic.
    It occurs to me, I am not sure this is possible, but if you had a live virus which presents the same antigens but has it’s genetic code modified to be less deadly, you can then release it surreptitiously and vaccinate everyone in certain areas that way. If possible, they would do that, as it again lets them cover up that the wet markets were the original source.
    4. They are just taking a chance they will have another epidemic based on a reopened market. This seems flat out insane.

    In all of these scenarios, the Chinese government is acting in very evil and nefarious ways. I personally can not see them NOT sampling the animals in the wet markets when they closed them – I think any competent scientist would tell them to do that – but maybe not, because once you sample them and found out it was from a species found at the wet market, you risk the scientists not keeping the secret. Anyone with more knowledge have any thoughts?

  • We understand the need to maintain distance and to test the entire population. Unfortunately, it is the authorities of many individual countries and many politicians of those countries who have ignored the threat of epidemics which arriving in Europe by aircraft from the beginning of 2020. In the second half of March (!), some European politicians appeared in public and told their constituents that the coronavirus problem was artificially exaggerated and therefore the date of the elections should not be moved – see example of presidential candidate from Poland:

  • Actually influenza is also a virus and also becomes pandemic each year. However, this year it was really mild, no high number of death related to it. Compare the influenza e.g. 3 years ago. Look at death statistics (regardless of cause, just cumulative deaths for each week) and you will see that the current number of deaths (total, not just covid) even in Italy and Spain is less than it was 3 years ago during the influenza season. It seems that people who would have died because of a tougher influenza are dying now because of covid. It is really sad, but why don´t we shut down the world each year because of influenza to save these people?

    For European data see:

  • I’m still stunned at how ill prepared world leaders (including the United States) were and at their lack of action to contain the virus as soon as its existence was known.

    Yes, China should have informed the world immediately, but that didn’t happen and can’t be changed. However, even after the rest of the world was aware of the virus, international travel continued. Flights from some countries to and from China continued until as late as mid-February. All of those travelers then returned to their home countries, where travelers from all over the world continued to arrive and depart, spreading the virus even more.

    Even after the United States had documented cases, domestic travel (as well as international travel with very few restrictions in the beginning) in the U.S. continued, and domestic travel still continues today.

    Imagine if this had been a faster spreading virus with a much lower survival rate…

    • There is a writer named Laurie Garrett who wrote a book called “The Coming Plague” which went into the histories of several diseases which emerged from the animal world to humans, and how we would eventually get a plague.
      They recently did an interview with her, in which she said plagues happen because of inadequate (or for that matter actively harmful) government actions/inactions.
      She said this one is due to both Xi JinPing and Trump screwing up – this seems undeniable. But they were not alone, as you pointed out.
      The countries which did best are the ones who truly respect infectious disease – Japan and all those smaller wealthy Asian countries – South Korea, Singapore, Taiwan. And of course Hong Kong which is not a country but still has some self government.
      America is STILL completely screwed up in this – I respect Dr. Fauci for his dedication and knowledge but I think he mishandled informing the public – should have made a point of giving us the “over 200,000 dead” and “wear the best face mask you can find or make” from the beginning, to scare the public into actually self isolating. The self isolation done in a few more farsighted states has been helpful in those places, in the short term, but for a comparable economic cost, if ALL the states had done the same, the public health benefit could have been vastly greater.
      Laurie Garrett consult for one of the pandemic disaster movies, and she said one thing the movie never contemplated was the level of incompetence she has actually seen so far.

    • Imagine if China wouldn’t have been experimenting with specie-threatening viruses that are bioengineered and not zoological.

      Now imagine they didn’t try to cover it up for 3 months.

      Trump shut down chinese travel almost immediately. And he was called a racist.

      Shutting down the biggest economy in the world doesn’t happen with the snap of the finger.

      You want scary?? How about what happens when the dust settles from this, the body count is tallied, and the investigations into Chinese bio manufacture, release, coverup, and lying are investigated.

      Going to make the cold war look like a ridiculously stupid pissing contest.

  • News reports claim the Chinese wild animal markets have been allowed to reopen – with the bats, pangolins, and civets, and god knows what else.
    The claim is, the only clear difference is there are security guards to prevent people from taking pictures or videos.
    I am not sure if it is true, but I wanted to ask doctors, virologists, epidemiologists- what does this mean? Both in terms of what is likely to happen- I am assuming, besides being generally a hazard, if there were bats with this virus in the wet market in Wuhan, there is no particular reason there would be none elsewhere in the country-so, does it mean a new epidemic with the same virus?
    Could it be China has a reliable vaccine already? A friend of mine said he had seen a report where a Chinese scientist injected himself with vastly more of some vaccine than would be needed to provoke a good immune response, in order to prove the vaccine was safe – not sure what kind of vaccine – but, is it possible they have a vaccine already? Is it possible they have some a live virus vaccine which could be “administered” by aerosol simply sprayed out in public? What is going on? Maybe the reports are wrong, but I can make no sense of it if they are true.

    • Continuing my own line of speculation – it occurs to me, even with the persecution of the original whistleblower doctors, the Chinese virology people had about a two month head start on the rest of the world in figuring out how this virus works. Maybe they have some reason to think it is safe to reopen the markets.
      One scenario occurs to me – if anyone in charge had any sense, when the decision was made to close the Wuhan market, all the suspect animals would have been seized and tested by the government scientists – so, they probably know perfectly well which animal was the host of this.
      Maybe they have very quietly forbidden trade in only that species?
      XI JinPing has a very strong propaganda interest in reopening the markets, as long as that does not result in a new flare up, because then he can plausibly deny it was ever the wet market which caused the problem.
      The likely murder of one of the whistleblowers – she has been disappeared – could be, not merely to silence criticism, but to prevent her identifying which species it was which spread the disease, because that is a smoking gun – and, unless you make that species extinct, you can never hide it – the world virology community would get that species, infect it with the virus, and, could then see if it is the animal host.
      Again, experts please speculate.

  • The best thing to do is prevent the conditions that create these viruses in the first place. Like the Chinese wet market that spawned this.

    Anything else is reacting after the horse has left the barn.

    • The claim is they reopened the wet markets. I am not sure what to make of that. Do you have thoughts? My guess is, it either really is a biowarfare creation or they identified the host species and are keeping that one species out of the markets. Or they have a vaccine. ????

  • The social distancing we are doing now has the benefit of giving time for the health care system to increase capacity. Otherwise we might as well skip building more ventilators and go straight to more incinerators.

    • Well let’s do that then. 100-250 k ppl is a small drop in the bucket compared to the whole populace
      It’s hardly anything. They make it sounds like a big scary number but for 200k to die in order for everyone else to become exposed and immune by OPENING the country as usual again ASAP is our only option
      Sometimes a few have to die to save everyone else’s life, economy and world and I’m sorry but 200k is a few in the grand scheme of things

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