The COVID-19 Pandemic at May 2020.
Widespread pandemics have hit civilisation about once every 80 years or so since ancient times. The first recorded pandemic, the Plague of Athens, occurred around 426 BCE. In December 2019, as if to mark the centenary of the devastating 1918 Flu, a ‘pneumonia of unknown origin’ emerged in Central China.
Despite warnings from prominent figures and scientists over the last decade, most countries had made little progress with pandemic preparedness and there were almost no vaccine platforms (building block vaccines) in place that would have allowed rapid vaccine development from previously advanced work. Adding to these failures, the outbreak was downplayed by many commentators. The opportunity to ‘spool-up’ organised responses by countries in those first couple of months was lost.
New Zealand is fortunate in having a Public Health specialist, Dr Ashley Bloomfield, as its Director General of Health. Together with Prime Minister, Jacinda Ardern, they were able to take effective action with a lock-down, that appears to be leading the country towards possible eradication of the disease. The first aim for any country, however, is to limit demand on Intensive Care beds and hospitals. Ten years ago, the world faced the H1N1 Swine Flu pandemic. Then, New Zealand had no prior warning and became the second country in the world to have an outbreak after Mexico. New Zealand responded well but unlike the current virus, the disease was short-lived. After three months everyone involved packed up and there was little follow up in terms of ‘Lessons Learnt’ to prepare for the next one.
The current pandemic, COVID-19, is caused by the SARS CoV-2 virus, part of a wider family of coronaviruses, which cause about 30% of common colds. SARS CoV-2 is more deadly as it is a novel virus (new to humans). It has jumped species recently, from an unknown animal host after originating in bats. This virus is therefore unrecognised by the human immune system. Interestingly, almost all human viruses at some point in the past have jumped species from other animal hosts. Some are even older than humans. Using phylogenetic trees, it has been possible to trace the herpes virus back to dinosaurs, some 200 million years ago.
To survive a previously unseen pathogen, humans rely heavily on their ‘first response’ immune system. Known as the Innate System, it provides a general response to any new threat. After a few days the ‘Adaptive Immune System’ revs up. That second system develops specific antibodies and T-Cells that make a more targeted attack. While this goes on, we feel ‘dreadful’ as our body’s own cytokines fight a battle with the virus. Usually we recover. When we do, our immune system will usually hold ‘memory’ to that virus and we get some durable immunity. That ‘memory’ to that specific invader can last months or even years.
Eventually these previously unseen viruses end up merging into the common pool of human viruses but it takes years. Over time a virus will usually evolve to become less lethal in order to survive. The only evolutionary goal for a virus is to spread. So survival pressure will favour mutations that enable transmission of the virus. If it kills off its host too fast, a virus will only have a short epidemic and not spread far and wide. Highly lethal viruses like Ebola tend to kill a lot of people quickly and then burn out.
This virus seems well adapted to enable spread. It’s main route for transmission is respiratory, so it is breathed in, in droplet form. It’s secondary route is from touch, that is transferring the virus off a surface and onto the mouth or nose. Its ability to transmit itself is defined by its ‘Basic Reproductive Number’, known as R(0). For COVID-19, the R(0) of the virus is probably around 3. That means it infects another three people from each infected person. It also has a mortality rate of around 1%. So it is particularly good at spreading and significantly, carriers seems to be infectious for two or three days before symptoms appear. Overall, perhaps 80% of those infected will have either mild symptoms or none at all.
These numbers can be applied to any virus. The seasonal Flu has an R(0) of about 1.2. The 1918 Flu had an R(0) of about 1.8. So COVID-19, with an R(0) of around 3, gives us a virus that is highly transmittable. It only kills a small percentage of those it infects but it infects a lot of people. So the total number of people that succumb to it will be high.
Where to from here?
A preventative vaccine is some way off. Possibly we will get a treatment before a vaccine. But treatments are never 100% effective in everyone. A number of candidate drugs being trialed, including immune modulators and antivirals used for HIV, Ebola and SARS-1. Another promising treatment being investigated was actually used in the 1918 Pandemic. Known as Convalescent Sera, it takes serum from recovered patients and injects the antibodies into infected patients. Anecdotal results are promising and randomised trials are ongoing.
Until an effective vaccine or drug treatment is found the goal remains to reduce the spread — so that each infected person infects less than one other. Infectious diseases like density. The closer people live together and interact with each other the better the spread. Surprisingly, the tools we have to block this are the age-old Public Health measures, like handwashing, social distancing, face masks and outbreak isolation. In fact, the word ‘quarantine’ comes from the 14th century Venetian word quarantena, for forty. This describes the practice originating during the Black Plague, of holding a ship in harbour for 40 days before allowing the occupants and crew to disembark. If we were effective in using tried and true Public Health measures, it is possible we could eliminate or drive down infection numbers to very low levels within the population. But the threat of a fresh outbreak always remains present. Critically, health system capacity could cope if any outbreak could be identified and shut down.
When we eventually emerge from this pandemic the hope of scientists is that governments remain mindful that these cross-species ‘spill-over’ events are happening at an increased rate to the past. In the last thirty years we have had HIV, Zika virus, West Nile virus, the Avian Flu, SARS-1, Ebola, H1N1 Swine Flu, and now this devastating SARS CoV-2. The increasing number of viruses jumping across into the human population seems to be linked to deforestation and population growth. These forces are bringing wild animals into closer contact with large numbers of humans.
When the dust settles, it is likely we will have wiped many trillion dollars out of the global economy. The lesson we must learn is that an ounce of preparation could have avoided this. There will be a ‘next time’. Humans are famous for downplaying risk. Scientists should be listened to and science needs to play a more prominent role in education and government. Significant tools were available to us to prevent this pandemic but few were put in place. Surveillance for emerging pathogens, increased public health focus, prepared vaccine platforms, protocols, training, PPE stocks, integrated health IT systems and transparent health outcomes are needed. Systemic fragility is caused by running healthcare with a short-term focus. Resilience for crisis events needs to be built-in and transparent for the population to see. These need not be ‘black swan’ events.
This will not be the last malevolent threat we face. We need to be more creative in our thinking. Systemic resilience, innovative organisation and a focus on science over efficiency are intelligent ways to protect civilisation.
Kris Vette was part of the team running the SARS pandemic response in 2003 while managing Infectious Diseases at St Georges Hospital, London. During the 2009 H1N1 Swine Flu pandemic he was Operations Manager for the New Zealand border. He now runs a Healthcare Emerging Technology consultancy.
