COVID-19: Have We Found Our Patient Zero?
Who is our COVID-19 Patient Zero? If one person infects three other people, and these three infect another three, after ten layers of transmission one person can infect 59,000 people.
The advent of COVID-19 is a strange unexpected threatening journey that began somewhere in the UK.
Who was our COVID-19 patient zero? Little did he or she know the economic and social impact that COVID-19 would have. It is a strange old beast dismantling your business, postponing 100 or so appointments and shutting the doors for a month. I don’t think we have ever shut in our entire trading history. But it is a small sacrifice for the greater good and necessary for effective social distancing.
In our little hamlet where we live, a loose cluster of 12 houses, we are acknowledging the role of all NHS workers tonight by loudly applauding and clapping on our doorsteps or in our gardens, a worthy borrowed custom from mainland Europe. We are very lucky to have the NHS in many respects even though successive years of government cut backs may have pruned some it’s abilities. This becomes more apparent when you compare our situation with what is happening in the United States. They of course have a private based healthcare system which has unfortunate fundamental flaws in the event of a ‘public’ healthcare crisis. This means healthcare is condensed down to affordability. Roughly 8% of the U.S population do not have any insurance – and many more have insurance policies that do not cover the full cost of healthcare. Added to this is the fact that if you lose your job you may also lose your employer-provided health insurance.
They have been slow to respond in the U.S. and as of March 26th they currently have 74,000 confirmed cases and over 1000 deaths. The US Centres for Disease Control and Prevention has now thankfully lifted restrictions on testing and made it free for everyone at last.
Unfortunately, if someone needs care for severe symptoms such as a ventilator in an intensive care unit (ICU)– this won’t be covered by the federal government. This is despite the fact that the US has one of the highest numbers of ICU beds per 100,000 population. The U.S figure for ICU beds is 34.7 per 100,000 people while we have only 6.6.
Whilst these figures may be in stark contrast to one another at least we don’t have the legislative barriers this side of the Atlantic. The speed with which COVID-19 has spread has put enormous pressure on governments worldwide to policy make in a way in which they have never done before. It is gratifying to know that over 500,000 volunteers signed up to support the NHS. This worked out at nearly 5 people per second within the several hours after it was announced by Matt Hancock.
Reproductive Number or R0 Value
What has been remarkable about COVID-19 is the rate of spread and its sheer infectiousness. What is alarming is that there are now two different sub-types of this disease. The original older ‘S’ sub-type was milder and less infectious, but the newer ‘L’ sub-type that has recently emerged spreads much more quickly and may account for around 70 per cent of cases.
When any new disease emerges the basic indicator on whether it will spread is the reproductive number or R0 (R naught). This is an epidemiological metric used to describe contagiousness. The R0 value is statistically important, if the value is less than one then an outbreak is unlikely to occur, but if greater than one an epidemic is very likely. As most of us probably already understand this is the number of people who will contract the disease from one single carrier; so, if the R0 value is three, clearly one person will infect three people and so on. If the R0 value is three and one person passes it on to three more people and each of those in turn pass it on to another three, after ten layers of this 59,000 people become infected!
So, someone out there could be our COVID-19 patient zero!
Our Patient Zero Probably contracted COVID-19 Skiing
There was a very interesting piece of journalism on Wednesday 25th March in the Telegraph which claims to have found just such a person. It seems very unfair to name and shame our 50-year-old IT consultant, who was skiing in Ischgl, Austria from January 15th to 19th with three friends, two from Denmark and one from Minnesota in America. But it is possible he has the very unfortunate tag of being our ‘Typhoid Mary’. According to official statistics our first recorded case was on January 31. The first initial recorded case of transmission in the UK was on February 28th. So it would seem he returned to the UK and passed under the wire undocumented.
Our IT consultant, our unwitting patient zero, returned to the UK on January 19th. He then fell ill the following morning. He demonstrated clear classic coronavirus symptoms, then passed the infection onto to his wife and children. It is now apparent that a dry cough spread rapidly in their locality in the weeks running up to the February half-term, with many local children taking time off school with illness. Meanwhile back at our ski resort. This week, the Telegraph reports that Austrian prosecutors have initiated a criminal investigation over suspicions of a cover up in the resort of Ischgl because they did not report an epidemic of COVID-19. It is now recognised by investigators that a huge number of transmissions and probable COVID-19 patients zeros from Germany, Iceland, Norway and Denmark are thought to have originated from Ischgl. It has even been traced back to one bar in the ski resort called the Kitzloch bar, known for its après-ski parties. Like many bars it is a bustling busy venue where people are in very close contact. ‘Beer pong’ is popular and in case you didn’t know, revellers spit a ping-pong ball into a beer glass. A perfect place for transmission for a COVID-19 patient zero.
Our COVID-19 patient zero told the Telegraph; “I was ill for 10 days – it was like wading through treacle. I couldn’t get up, I couldn’t work, it knocked me for six. I was breathless.” His wife also stated in the same interview “I was then ill, and so was my youngest daughter. My symptoms were a temperature and strange flushes, exhaustion which lasted for nearly three weeks intermittently, and total brain fog. My daughter had a temperature and persistent cough and was off school for two weeks. My eldest daughter felt wiped out for a day, but it passed quickly.” The family have not been officially confirmed to have had COVID-19 although this may change when the new antibody test is made widely available.
How the R0 value of COVID-19 compares to other diseases
Back to our R0 values. As a working example using seasonal flu, the R0 value is approximately 1.4. As you can imagine public health researchers have been hard at work trying to establish this core value for COVID-19. Various researchers in combination with the World Health Organisation (WHO) have published estimates of R0 values for this new virus. Some have used different methodologies; these results have been reasonably consistent with values ranging between 2 and 3. However there were statistical outliers.
Estimates form the WHO were more reserved with an R0 value of 1.4-2.5 while a team of researchers from China estimated a value of 3.3-5.0. These figures are significant. Ideally an epidemic requires controlling and the key element is reducing the R0 value to below 1. The R0 value indicates for instance how many people it may be necessary to vaccinate. A R0 value of 2 means that half the population require vaccination and a value of 3 indicates that two thirds require immunisation to stop forwards transmission.
The R0 values for COVID-19 are similar to other infectious diseases such as SARS (2 to 5) and HIV (also 2 to 5), but reassuringly much less than condition such as measles (12 to 16) or chickenpox (10- 12 but this is of course rarely fatal). At the end of the day the R0 value is just a theoretical value. SARS only infected 8,098 and had similar R0 values to COVID-19. Seasonal flu with a lower R0 value afterall infected many more people than SARS although it has an R0 value of 1.3-1.4. Also, the R0 value depends very much on the policies in place in any given country that help prevent transmission.
This is a key concept of social distancing which is necessary in the absence of a vaccine. Even simple steps such as hand-washing might make a difference. All these measures potentially lower the chances that the virus will spread and ensure that the real-time transmission rate is decreased.