Contagion: A Lesson For The 2020 Pandemic

Contagion was released in 2011, following the story of MEV-1, a novel fictional virus that brought the world to its knees. Sounds familiar? The movie has garnered attention recently due to the COVID-19 (Coronavirus Infectious Disease – 2019) pandemic and some of the similarities that lie between its plotline and reality. It was praised by the scientific community for its accuracy. Please do go and watch the movie if you have not already. 

That being said, since it is science fiction, there is an essence of true post-apocalyptic vibes from it. It does draw many parallels with the COVID-19 pandemic of 2020, but there are many places where there is a divide between the fictional MEV-1 and SARS-CoV-2. The virus depicted in the movie is far more aggressive and dangerous than COVID-19, with higher mortality rates, faster spread, and hence with more disastrous consequences. 

Through this article I’ll breakdown the science behind the fiction, as well as look into some of the similarities and dissimilarities between MEV-1 and COVID-19. For those who’ve watched the movie, those who haven’t and are here just to learn more about some science in epidemiology (science jargon: the study of spread and control of diseases) and viruses, and for those who simply like reading I hope you find this article interesting. 

Introduction

MEV-1 is a fictional virus that shows symptoms within one day of transmission. Symptoms include cough, fever, and inflammation of the brain resulting in seizures eventually resulting in death within 3-4 days. 1 in 4 people end up dead because of MEV-1. Although fictional, MEV-1 is a hybrid of real-life influenza and Nipah viruses. Nipah has symptoms similar to MEV-1 which include inflammation of the brain and coma among others. 

SARS-CoV-2 on the other hand has symptoms developing in a period of 1 – 14 days after exposure. Moreover, death is not as sudden as MEV-1. Symptoms of COVID-19 include fever, dry cough, and feeling of tiredness or fatigue. Let us now look into the science behind the movie in a little more detail. 

First Contact

At the beginning of the movie Beth Emhoff who has been coughing and showing some flu symptoms for a while returns from a trip from Hong Kong to her home in Minneapolis, USA. She ends up giving the flu to her son. Soon after, she suffers a violent seizure and is rushed to the hospital by her husband Mitch Emhoff. She sadly passes away in the hospital, but this is not the end of sorrows for Mitch, for immediately a call from the babysitter he left with his son has him rushing back to his sick son, to find him dead as well. 

The viewers are in shock, as people after people die. Clusters of people start getting sick with the same symptoms, eventually dying. Health organizations across the world try to understand what is happening, with blood samples being tested and autopsies being conducted. Experts believe it’s a meningitis outbreak but are still unsure as some symptoms aren’t consistent with meningitis. The autopsy showed that the virus caused encephalitis (science jargon: inflammation of the brain) which is what led to the seizures. 

Point of difference: COVID-19 has higher mortality rates in individuals above 60 years of age and individuals with comorbidities (pre-existing conditions such as hypertension, diabetes mellitus, cardiovascular disease, etc.). COVID-19 has a mortality rate (science jargon: the number of deaths divided by the total number of cases) of about 7%.

MEV-1 does not differentiate between humans and has a higher mortality rate which initially was just above 20% which later on increases to 25-30% (due to reasons discussed later). 

Stopping the Spread

As clusters of the disease start appearing across the world, in Hong Kong, Tokyo, London, Chicago, and Minneapolis initially, measures to stop the spread were instilled. Despite being unaware of what the disease was, the health agencies across the world had started measures to stop the spread of the disease. This includes the especially important techniques of isolation of individuals who have the disease and people who could have come in contact with the disease.

It becomes important especially in cases where the mode of spread is not known yet to contain the spread of the disease by isolating any individuals who are sick and quarantining those who had contact with someone who was infected or could have potentially come in contact with the virus. More characters are introduced with specific focuses on Dr. Leonora Orantes trying to backtrack the movements of Beth Emhoff in China and the spread of the disease there, and Dr. Erin Mears to track the spread of the disease in Minneapolis. This step is known as contact tracing. Given the high infectivity and the failures of isolation and quarantine, these individual clusters could not be managed and soon a large number of people started falling sick all over the globe.

So, what is the difference between isolation and quarantine?

While people who are sick are isolated, quarantining is done to people who could have come in contact with the virus.

Point of Similarity: COVID-19 had to initially also be dealt with in a similar way. The movement of sick patients was backtracked, and these patients were put in isolation. Individuals who have come in contact with sick individuals were put under quarantine. These methods are paramount to stop the spread of the virus. If not done properly, and the virus spreads snowball out of control, rapidly and dangerously. Contact tracing was also done in COVID-19 but not all around the world. While the contact tracing by the United States of America was done unsuccessfully, South Korea did extremely intensive contact tracing which is why they managed the spread of coronavirus and were able to prevent a large loss of life and keep the number of cases at a minimum.

Origin of the Virus

Dr. Ian Sussman discovered initially that the disease was chimeric in origin, which later on was identified as a combination of bat and pig viruses. Towards the end of the movie in a flashback, a bulldozer razes palm trees while clearing a rainforest in China that disturbs the natural habitat of some bats. One bat finds shelter in a pig farm and drops an infected piece of banana, which is eaten by a pig. The pig is slaughtered and prepared by a chef in a Macau casino, who transmits the virus to Beth in a handshake.

Point of difference: The way the coronavirus came into existence is still a bit debatable. Research indicates that bat populations were the native host for SARS-CoV-2, and eventually a spillover infection (meaning that when a population is saturated with a pathogen, and the pathogen manages to make its way into a new species population) resulted in the virus affecting humans. The difference between the viruses between the two species (bat and human) seems to suggest there was an intermediary host before humans got affected. Similarities between pangolin coronaviruses seem to suggest that pangolins were the intermediary host.

The Results Are Out!

The results of the preliminary analysis of the virus by, Dr. Ally Hextall, Dr. Ian Sussman, and Dr. David Eisenberg, isolated from the blood of infected individuals yield some insights into the virus. We learn that it is pleomorphic meaning it exists in many forms but tends to be ovoid in shape. We also learn that there are no pathognomonic features (science jargon: features associated with a particular disease). Dr. David Eisenberg tested all human antibodies (science jargon: proteins present in the body that neutralize pathogenic(disease-causing) viruses, etc.) against the virus and found no reaction. The body’s defenses had no idea how to deal with the virus!

Through modeling, Dr. Ally Hextall was able to figure out how the virus attaches to the cell. There were viral attachment proteins present on the surface of the virus which were attached to specific receptors present on human cells found in the respiratory tract and the central nervous system (the spinal cord and the brain). It was like a key fitting into a lock. Further analysis helped Dr. Ian Sussman discovered that the virus belonged to the Paramyxoviridae family of viruses, which includes viruses that cause measles and mumps.

Another interesting sub-plot of the movie has Mitch being immune to the virus, which seems to contradict the discussions made above. 

Point of difference: While the MEV-1 belongs to the Paramyxoviridae family, the SARS-CoV-2 virus responsible for COVID-19 belongs to the Coronaviridae family of viruses. Albeit it is pleomorphic but is spherical in shape, something we can see clearly from images of the virus. Also, there is no specific available evidence on whether individuals have immunity against COVID. The WHO (World Health Organization) also has noted that there is no evidence of the generation of immunity in individuals who were infected with SARS-CoV-2 and are now healthy.

Reproduction Number(R₀)

The reproduction number (R₀) is a mathematical term used to describe viral reproduction. In simple terms R₀ is the number of people that are infected by one sick person. Some examples of some R₀ values are 1 for flu, 3 for smallpox, and 4-6 for polio (before a vaccine was discovered). Initially MEV-1 has an R₀ value of 2, but soon problems arise moving that number up to 4. This change also attributes the increase in mortality rates from a low 20% to 25-30%. But, what does an increased R₀ mean? In simple terms it means that the rate of infections spreading increases. More people get sicker in a shorter time span.

Point of difference: So, what is the R₀ of COVID-19? As per initial studies the R₀ of COVID was estimated at 2.2 – 2.7, but more recent studies (source) seem to suggest a much higher R_{0 ­­}of 4.7-6.6 with a median of 5.7. Such a higher R₀ is indeed a cause of alarm and concern. This would mean a much larger population would be infected by the viruses, and more people will lose their lives. R₀ however can be decreased if one follows proper social-distancing norms and takes the necessary precautions. The R₀ value will take a massive dip once a viable vaccine is in place.

Mutations in the virus

So, what was the change that brought about such a sudden rise in the R₀ for MEV-1? Well it mutated by moving into an HIV-AIDS population in Africa making the Durban Cluster highly divergent. Mutation essentially means that the genetic material of the virus has changed in the course of its life cycle. The term divergent here seems to indicate that the virus has mutated to such an extent that it looks vastly different from the original strains of the virus. The mutation has made MEV-1 more powerful, and dangerous. This is why there is an increase in mortality rates from just above 20% to between 25-30%.

Point of similarity:  Research seems to suggest that coronavirus too has mutated. There are estimates that there exist multiple strains, with different levels of strength. The stronger strains have higher death rates. This is one of the reasons why some countries have higher R₀ values and mortality rates.

Finding a vaccine

The race to stop the spread of the disease starts, with CDC (Centre for Disease Control and Prevention) trying to make a vaccine, with their efforts spearheaded by Dr. Ally Hextall. The first step in making a vaccine would require being able to grow sufficient quantities of the virus so as to conduct tests on it. The first problem they faced was being unable to grow the virus on anything. Any culture the virus was grown in, it killed it off. It was too strong. However, eventually, Dr. Ian Sussman was able to provide a breakthrough, by growing the virus on a fetal bat lung cell line.

Point of difference: We were lucky in this regard with respect to coronavirus. Coronavirus was successfully cultured pretty early in the COVID-19 timeline. Coronavirus is grown on monkey kidney cells.

The way vaccines work is producing antibodies in the body to fight the specific virus. The way it is done is either through, a) proteins of the virus, b) weakened live virus or c) a similar weaker virus. Introducing a vaccine helps the body fight a weakened form of the disease. This helps the body prepare the tools (antibodies) for when the actual virus strikes and provides protection and immunity from the actual virus.

An interesting question posed by Mitch can also stem an important discussion. Mitch inquires whether his blood could be used to make a cure. Theoretically blood serums could be manufactured wherein the antibodies specific to MEV-1, could be separated from the blood and used to protect individuals. However, this is an expensive method and is time-consuming and cannot be considered as a viable method of making vaccines.

Points of similarity: While there is research being done on using antibodies from people who have survived COVID-19, the above method has been used successfully for many other diseases most notably Ebola. 

Dr. Ally Hextall’s team makes a vaccine using virulent (disease-causing) proteins of the virus on monkeys, but the results are unsatisfactory. She shifts to using a live attenuated (weakened) virus as a method to produce a vaccine. Live weakened viruses had the potential to regain their strength and cause the disease once again. After many iterations she was successful on the 57th trial. For fear the human trials will take time, and worried that more time spent would result in more deaths she tests the vaccine on herself on a dangerous gamble. The attenuated virus could turn into a normal aggressive and dangerous virus, but her gamble pays off with the vaccine being successful.

An Ultimatum

The creation of the vaccine signifies the end of the movie. The world slowly returns to normalcy as the vaccine is manufactured in mass quantities and distributed across the world.

The fact remains that we are not in a movie and this is actually happening in real life. We are faced with an ultimatum. To follow the rules and norms issued or face the consequences. We need to prevent further spread of the disease as well as decrease the R₀ value. If this is not done the number of cases of COVID-19 and resulting deaths will only rise upward.

To understand more on how to prevent the spread of COVID-19 please go through the resources on the following link. https://www.who.int/emergencies/diseases/novel-coronavirus-2019