His name was Hokusai and he published “The Great Wave off Kanagawa (Kanagawa-oki Nami Ura)” at some point between 1829 and 1833. It’s a woodblock print of the genre ukiyo-e, which translates, rather beautifully, as a “picture of the floating world.”

Look closely at “The Great Wave” and you will see that it towers above the cowering oarsmen in three wooden fishing boats. They are on their way back to Kanagawa (now Yokohama). Mount Fuji is just visible in the distance.

These days we are all a bit like those Japanese fishermen, cowering beneath a giant wave. The wave in question is the pandemic caused by the virus SARS-CoV-2 and the deadly disease it can cause, COVID-19.

For the past two months, ever since the epidemiologists persuaded the politicians to take the threat of COVID-19 more seriously than the usual winter wave of influenza, we have been captivated by wave-like images: graphs depicting the early, exponential growth of infections and deaths and then the flattening of the curve as we practice social distancing and implement economic lockdowns.

These graphs were at first generated by the epidemiologists’ models. Now, however, we have the actual numbers of confirmed cases and deaths. They don’t perfectly fit the predicted curves — no model is perfect — but they roughly do.

In most of the worst-affected places in the developed world, such as New York, it now seems that the great wave has crested. In terms of new cases, hospitalizations, intubations, and deaths, the peak is now behind us. For the United States as a whole, the great wave of new cases has clearly reached a plateau since the first week of April.

In Britain, too, it seems probable — making all the necessary adjustments for lags in the data — that April 8 was the peak of the wave in terms of mortality.

The situation is even more encouraging in a number of European countries, notably Austria, Denmark, and Germany, which is why their citizens — unlike New Yorkers and Britons — can now look forward to a partial return to normality in a matter of days. In Austria, on May 1, stay-at-home orders will be lifted. German secondary schools will reopen May 4.

A number of American states are already moving in the same direction. In Montana, the beautiful and thinly populated state to which I retreated six weeks ago, churches reopened for worship Sunday, and most businesses will be able to resume work Monday.

So is that it, then? The wave crested; most of us survived; now back to normality? These were the words of Vice President Mike Pence on Wednesday: “We truly do believe, as we move forward, with responsibly beginning to reopen the economy in state after state around the country, that by early June, we could be at a place where this coronavirus epidemic is largely in the past. Americans are going to be able to enjoy a good summer.”

Hang on, not so fast.

In history, all the great pandemics have come in waves, including the Black Death of bubonic and pneumonic plague in the 14th century and smallpox in the 18th century. The first recorded plague outbreak — in 5th-century BC Athens — had three waves: in 430, 429, and 427-26.

In some cases, the second wave was worse than the first. Take the great influenza of 1918-19. The first recorded outbreak was at a Kansas army base, Camp Funston, in March 1918. But the global peak of mortality was in the second wave of October and November. A third wave affected some areas of the world in early 1919, principally England and Wales and Australia.

The 1957-58 influenza pandemic hit Hong Kong in mid-April 1957. It reached the United States the following June and produced a surge of deaths among teenagers that fall. But there was a second wave in January-March 1958. There were further spikes of excess mortality in early 1960 and early 1963.

The main reason to expect a second wave of COVID-19 in 2020 is that we are nowhere near herd immunity anywhere. Even in New York state, the worst affected part of North America, the infection rate is little higher than 21 percent, according to the most recent testing. As lockdowns ease and people return to work and school, it is almost inconceivable that we won’t see rising infections, illnesses, and deaths.

Indeed, we are already seeing signs of that in some parts of Asia, notably Singapore and northern China.

The only real debate is the extent to which warmer weather is going to dampen the contagion in the northern hemisphere. I have read many academic papers on this subject and remain unconvinced. We are learning that this virus spreads most rapidly indoors, in confined spaces such as subways, restaurants, and hospitals. (Hence closing parks and beaches was pretty pointless and probably on balance harmful.) So it’s possible summer won’t radically reduce the infectiousness of the virus, unless we all move our desks outside.

Alternatively, if weather does matter, then the second wave may come in October, when the weather cools and when most schools and universities attempt to go back to normal. “There’s a possibility that the assault of the virus on our nation next winter will actually be even more difficult than the one we just went through,” the director of the Centers for Disease Control and Prevention, Robert Redfield, said in an interview last week. “We’re going to have the flu epidemic and the coronavirus epidemic at the same time.”

Now, just think of the political implications of that scenario. A second wave would be the death blow to the happy talk of a “V-shaped” economic recovery. And it would arrive just in time to discourage elderly voters — who lean Republican — from going to vote. A poll published last week showed presumptive Democratic nominee Joe Biden neck and neck with President Donald Trump in six key states: Arizona, Florida, Michigan, North Carolina, Pennsylvania, and Wisconsin. On three key issues — handling the pandemic, preventing another one, and making health care more affordable — Biden narrowly leads Trump. This after weeks when Biden has been more or less invisible and Trump ubiquitous.

We have all heard far too much in recent weeks about bending the curve, as if there is only one curve. In the history of pandemics, I am afraid to say, there are very few cases of “one and done.” The only questions that remain open are exactly when the second wave will come, how big it will be, and if it will be followed by a third.

Look closely at Hokusai’s “The Great Wave off Kanagawa,” which depicts not a tsunami but a so-called rogue wave. The artist is most certainly not implying that, after the great wave breaks, the sea will be a millpond. Until we reach herd immunity or find and distribute a vaccine, the same will be true of COVID-19, alas.

By Niall Ferguson, the Milbank Family Senior Fellow at the Hoover Institution at Stanford University, and managing director of Greenmantle.