Aside from predicting a massive loss of life, public health officials anticipated a “tsunami” of COVID patients that would lead to a collapse of hospitals and even more deaths. This fear was fueled by initial reports from China showing 20% of COVID patients required hospitalization compared to 1–2% of flu cases. However, the actual hospitalization rate was 1.7–2.1%,  but by the the time this was discovered panic had already set in.
Social distancing, lockdowns, and later, masks were proposed to flatten the curve and save the hospitals from collapse. Hospital capacity was likened to subway cars, where in times of extremely high demand many passengers would simply not be able to fit into the packed car.   Hospital systems are unlike subway cars; they are designed to be far more flexible.
Even before COVID, hospitals routinely implemented various policies to deal with periods of high demand.  These policies included increasing the number of ICU beds, adding more staff, and postponing non-emergency care. In addition, health departments would move or reroute patients to other, less heavily burdened, hospitals.
These measures have been part of hospital management and public health policy for years going back, at least to the 1980s. These strategies were put in place to deal with natural disasters, war, riots or other mass casualty events, and heavy flu seasons — including the recent 2017–2018 flu season.       
New York City was hit hard by COVID early on, and many pointed to NYC’s experience of how bad things would be if severe lockdowns were not imposed. However, when examining what actually happened in NYC, we find that only one hospital was close to collapsing — Elmhurst Hospital in Queens. Retrospective analysis has pointed out that this was because the previously mentioned policies were not fully implemented. They did not reroute patients to other hospitals in the area, which had lots of available beds. It seems pride and determination played a role, statements like, “whatever comes through the door, we can and will take care of it,” were the prevailing sentiment. Weeks later, Elmhurst started transferring patients to other hospitals. Consequently, even with its surge and initial refusal to redirect patients, Elmhurst did not collapse, nor did it even make the list of “hospital[s] with the greatest COVID-19 burden in 19 cities”.
As a testament to the NYC hospitals not collapsing under the wave of COVID patients, temporary field hospitals that were erected in several locations throughout the city to handle the patient overload were soon closed for lack of need. 
Sweden was heavily criticized for not implementing a strict lockdown like so many other countries.  The first two waves bore a heavy death toll, but there were no reports of hospitals being stressed beyond capacity.    This is despite Sweden entering 2020 with the lowest number of hospital beds per capita in Europe — 2.1 beds per 1,000 population vs. the European average of 5 per 1,000.
As with NYC, London, and other locations, Sweden erected a temporary field hospital near Stockholm, just in case the hospitals could not manage the load. But they did, and the temporary hospitals proved unnecessary and were closed.
In September 2020, the Israeli government considered (and later implemented) a second “full” lockdown over the upcoming holiday season. (The first such lockdown was arranged six months earlier over the Passover holiday.) A key factor in the decision to lock down the country again was the governmental claim that Israeli hospitals were totally overwhelmed and had well over 100% capacity for COVID patients.
Experiencing overcapacity is not new for Israeli hospitals. In 2019, 2018, 2017, 2016, 2015 and earlier, hospitals experienced significant patient surges that led to overcapacity. While overwhelmed hospitals happen every year, the situation was allegedly so bad in 2020 that the Health Ministry ordered all hospitals to stop all non-urgent treatments and surgeries.
The hospitals themselves counter-claimed that they were far from being “at capacity”. This prompted an undercover investigative report by Israeli Channel 12, which proved that the COVID wards were actually well under capacity. In response, the Israeli government quickly expunged all COVID hospital data from their website and the second “full” lockdown in Israel proceeded. Weeks later it was revealed that about a third of hospitalized COVID “patients” had in fact already recovered from COVID and were in the hospital for unrelated issues.
Hospitals are often underfunded and overburdened, which makes dealing with peak demand even more difficult, but the fear that hospitals would collapse was not realized. What was shown to be effective was not lockdowns and panic, but the implementation of the standard peak demand policies that have helped hospitals cope in the past.
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 "The United States and other countries, experts say, are likely to be hit by tsunamis of Covid-19 cases in the coming weeks . . ."
 "All indications show if the curve is not flattened, hospitals across the country will not have the capacity to deal with the surge in hospitalizations associated with COVID-19,"
 “That's about 10 times more often than flu.”
 “The overall [infection-hospitalization ratio] IHR meaning the percentage of infected individuals who are hospitalized was 2.1%”
 ~1.7% us nation-wide
 "Your workplace bathroom has only so many stalls," Charles Bergquist, director of the public radio science show "Science Friday" tweeted. "If everyone decides to go at the same time, there are problems. If the same number of people need go to the restroom but spread over several hours, it's all ok."
 From 2011https://www.who.int/docs/default-source/documents/publications/hospital-emergency-response-checklist.pdf
 From 2019: “An efficient and scalable emergency response system that can respond to surge capacity—Pandemic preparedness relies on a system that can surge in times of crisis.”
 From 1984: Toward a better understanding of hospital occupancy rates.
 2018 “Emergency departments at three Providence hospitals were so overwhelmed with patients Wednesday that they began diverting ambulances elsewhere.”
 2018: “hospitals and urgent-care centers in every state, and medical centers are responding with extraordinary measures: asking staff to work overtime, setting up triage tents, restricting friends and family visits and canceling elective surgeries,”
“In California … several hospitals have set up large “surge tents” outside their emergency departments”
A Pennsylvania hospital spokesperson said about their “surge tents” ““I think Tuesday we saw upwards of about 40 people in the tent itself.”
 2018: “California, emergency rooms had gone into "diversion mode," during which ambulances are sent to other hospitals”.
 2018: “A tsunami of sick people has swamped hospitals in many parts of the country in recent weeks as a severe flu season has taken hold.
In Rhode Island, hospitals diverted ambulances for a period because they were overcome with patients.
In San Diego, a hospital erected a tent outside its emergency room to manage an influx of people with flu symptoms.”, “Wait times at scores of hospitals have gotten longer.”
 California hospitals face a ‘war zone’ of flu patients — and are setting up tents to treat them
 NHS winter crisis: extra beds created by 52% of UK Hospitals. https://www.theguardian.com/society/2019/dec/02/nhs-winter-crisis-extra-beds-created-by-52-per-cent-of-uk-hospitals
 La gripe colapsa los hospitales de media España.
 2020: “Even as Elmhurst faced “apocalyptic” conditions, 3,500 beds were free in other New York hospitals, some no more than 20 minutes away.”
“There’s a strong ethos of whatever comes through the door, we can and will take care of it,”
One Hospital Was Besieged by the Virus. Nearby Was ‘Plenty of Space.’ https://www.nytimes.com/2020/05/14/nyregion/coronavirus-ny-hospitals.html
 “Eriksson said the field hospital had not needed to take in patients since the region’s regular hospitals had been able to increase capacity more than healthcare officials had initially thought feasible.”
 “Health Ministry claims COVID wards countrywide overcrowded”
 Patients in the corridors, doctors collapsing: "You can't be silent any longer"
The occupancy rate of Israeli hospitals, he said, is 100% to 120%
 The doctors specializing in the hospitals: "The situation in the emergency rooms is dangerous. They are required to make the impossible choice every day and decide which of the patients to treat first."
 Hospitals all over the country are reporting massive workloads, staff collapsing and patients who find themselves hospitalized in the corridor.
 In Haifa and Soroka Hospital in Be'er Sheva, the occupancy in the emergency room exceeded 200%, while in Sheba Hospital in Tel Hashomer it reached 350%
 “The Health Ministry has ordered hospitals to discontinue all elective (non-urgent) treatments and surgeries, claiming the system is flooded with coronavirus patients.”
 “Ministry’s statistics had massively inflated the number of patients at a number of hospitals.”
 “In some wards, occupancy rates are only 50%, contrary to ministry report”
 “Israel’s Health Ministry has scrubbed its coronavirus information page of all data regarding the status of coronavirus hospital wards across the country.”
 “[A given patient] is defined and included in the number of hospitalized COVID patients, even though the coronavirus is not related to the reason for hospitalization”