Most of the talk about COVID-19 has focused on how many people get infected and how many people die compared to the flu.

These comparisons are not useful for a number of reasons, two being that we are at the beginning of an exponential curve and COVID-19 is a novel virus that our immune systems have no defence against.

If you were going to persist in making flu comparisons, the most important thing to consider about COVID-19 would be the disproportionate number of cases that require hospitalisation and ICU care lasting 3–6 weeks.

0.9% of people that get the flu need hospitalisation, 15% of COVID-19 patients in China required hospitalisation and 5% needed critical care. In Italy, 10% of infected patients require intensive care.

What does this storm of patients with severe respiratory illness mean for the NHS?

Let's have a look at capacity and how quickly COVID-19 could overwhelm the number of hospital beds and supply stockpiles of the NHS.

As of March 13 there are just over 500 confirmed cases in the UK. The prime minister warned yesterday that up to 10,000 people may be infected. To avoid fearmongering I’m going to assume a conservative 2000 people are infected.

According to several studies, the doubling rate of COVID-19 is six days.

Confirmed cases might rise faster or slower than the doubling rate, depending on how robust the testing is in each country. We saw the confirmed cases rise quickly in Italy when they started widespread testing. The doubling rate is how fast actual new cases rise, not diagnostically confirmed cases.

Assuming there are 2000 cases, there should be around a million cases in the UK by the end of April, 2 million by the 7th of May, 4 Million by the 13th of May and so on.

As more people become infected it becomes increasingly difficult to successfully detect, track and contain the transmission of the virus as South Korea and China have.

Without implementing the measures that countries like China and South Korea took, the doubling rate won’t slow until a significant percentage of the population has been infected.

How well will the NHS deal with this outbreak?

Let's examine two factors — hospital capacity and masks.

Let's look at hospital beds per 1,000 people:

South Korea and Japan, two countries that are dealing with the outbreak relatively well have 12 hospital beds per 1,000 people.

China has 4.3

Italy has 3.1

Austria has 7

Germany has 8

The UK has 2.5

The NHS has about 140,000 beds in total.

As of Q1 this year, the NHS had a bed occupancy rate of around 88% at any given time, leaving about 16,000 beds available nationwide.

The majority (80%) of people with COVID-19 can stay home and ride out the illness but a significant proportion need hospitalisation. In China 15% of infected needed hospitalisation and 5% needed intensive care.

In Italy the data is even worse, in one hospital 100 of 120 admitted developed pneumonia 10% require critical care treatment.

The UK might fare a little bit better than Italy, the UK population is (slightly) younger than Italy’s and has much lower rates of smoking which proved to be a predictor of a more severe condition in China.

However, the UK has higher rates of chronic conditions like heart disease and diabetes which are associated with increased severity.

With a conservative estimate of how many people are infected and given a 10% hospitalisation rate, the UK healthcare system will reach capacity by the 12th of April.

With some patients requiring 3–6 weeks of care the turnover rate will slow to a crawl.

If this estimation is off by a factor of two regarding severe cases, that means that capacity will be reached six days later. So if 5% of cases require hospitalisation, capacity will be reached on the 18th of April. If it’s 20%, on the 6th of April.

As hospitals reach capacity, surgeries and treatments for chronic conditions will have to be cancelled. All available medical professionals regardless of their specialisation will be reassigned to deal with COVID patients.

This is what is happening in Italy. They’re even bringing doctors out of retirement.

This projection also assumes there’s no increased demand for beds from non-COVID-19 patients. As the healthcare system becomes burdened and if we experience the same medication shortages as China. For the sake of this prediction let’s assume this won’t happen.

Let’s look at medical supplies.

The U.K has a healthcare workforce of about 500,000 people.

As COVID-19 cases saturate nearly every city, virtually all health care workers will be expected to wear masks. If only half of them are working on any given day (again a conservative underestimate) and each worker limited themselves to just one mask a day (which isn’t sanitary) we would be using 1.75 million masks a week.

How many masks does the NHS have stockpiled?

We don’t know, they haven’t released the numbers.

We do know that they stockpiled masks for potential Brexit trade disruptions and that the NHS believes this will be enough as it has ordered trusts not to order extra masks.

If the stockpile isn’t enough it’s unlikely we’d be able to increase domestic production or importation to keep pace with this sudden increase in demand, especially since multiple countries are going to be experiencing shortages and wanting their own masks.

It should also be considered that most of the world's supply of medical masks are manufactured in China and their government has requisitioned some of their factories to deal with its domestic outbreak should also be considered.

Supply shortages don’t stand in isolation but compound the severity of the outbreak. Even with full protective equipment, frontline healthcare workers are getting infected.

10% of Italy's doctors and nurses have been infected.

As masks become scarce, more doctors and nurses will have to leave the workforce, leading to heavy staffing shortages that will make the situation worse.

The same should be considered of thousands of medical devices and supplies, from complex equipment like respirators, down to gloves, gowns and drip bags. Shortages compound the difficulty of treating patients by reducing the available options to physicians.

One doctor in Italy remarked recently that every ventilator has become like gold

I want to be clear- this article isn’t fear-mongering, I have been conservative with my estimations every step of the way.

Even still, I want to emphasise that if I was overestimating the severity of spread, the number of patients requiring hospitalisation or the rate that the NHS will burn through equipment it only shifts the timeline by weeks at most.

Despite the response from multiple governments, individuals are not fully grasping the magnitude of the systemic burden that the NHS and global supply chains are going to be facing. Even if the risk to healthy people is low, it’s inexcusable to mock people for isolating themselves or businesses for closing or cancelling events. These measures are the bare minimum that we should be doing to slow the rate of infection and give our healthcare systems a fighting chance.

The doubling time will naturally slow when enough people are infected due to herd immunity and a shrinking susceptible population. But closing schools now, implementing remote working policies and cancelling events should absolutely be done to slow the spread of the virus.

Our government decided yesterday that they were not enacting school closures, not because they disagree with the science of how effective they are, but because they would have to close them for weeks and might have to enact closures a second time later in the year.

They believe the British people might grow tired of staying at home.

The government should at least be considering reactive school closures — closing a school when a child or parent is confirmed infected.

A study in the Nature Journal found that reactive school closures reduce the cumulative infection rate by 25% and delay the peak of the epidemic (in that region, for a moderately transmissible virus) by two weeks.

As more people become infected, closures and shutdowns become less and less effective at slowing the spread of infection. As other countries around the world and in Europe take more drastic measures, I find the government lines of “weighing measures against the economic impact” and doubting the spirit of the British people to endure isolation measures very cynical, especially given the weakness of our healthcare system compared to other European countries.

The UK has suggested that ‘herd immunity’ is the best way to deal with COVID-19.

Jeremy Rossomn, Honorary Senior Lecturer in Virology and President of Research-Aid Networks at the University of Kent had this to say about that strategy:

The percentage of the population that needs to be immune to enable herd immunity depends on how transmissible disease is. This is measured by the term R0, which is how many new infections each case will generate. For COVID-19, the R0 is estimated to be 3.28, though studies are still ongoing and this number will probably change. This means that for herd immunity, about 70% of the UK population would need to be immune to COVID-19. Achieving herd immunity would require well over 47 million people to be infected in the UK. Current estimates are that COVID-19 has a 2.3% case-fatality rate and a 19% rate of severe disease. This means that achieving herd immunity to COVID-19 in the UK could result in the deaths of more a million people with a further eight million severe infections requiring critical care.

I posted this picture recently of an isolation tent in Lincoln:

You will be happy to know that the tent has been upgraded to this:

The best time to act was weeks ago, like Singapore and Japan, by increasing our hospital capacity. The second-best time is right now.

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