Diseases and virus outbreaks have caused deadly health challenges to humans since the beginning of our species. From Malaria and tuberculosis that caused thousands of death in Ancient Egypt around 5,000 years ago to the global pandemic of Plague in the first millennium to the virus outbreaks brought by Spanish conquistadors in Latin America to the more recent Spanish Flu in the 80’s that caused millions of deaths around the world, pandemics in every age hit the human civilisation with lethal effect. Covid-19 is another pandemic in ages with lethal killing power.
But as human knowledge on viruses and their contagious nature continued to improve, many of the mysteries behind these infectious diseases are now known to us. Predicting the spread of the disease in successive steps is most crucial for taking the right measure for mitigating health risks. Researchers are now exploring the predictive models by using existing data about the spread of the virus.
How to create such analysis models that can rightly predict the spread of the contagion? Well, here we are going to explain various models and how they work.
S-I-R Model
This is one of the straightforward mathematical models that can be used to represent data concerning disease spread. It splits the population into three elementary categories as per the disease status. All the people who have not contacted the infection yet are called “susceptibles”. In that sense, all are assumed to be susceptible or capable of getting the infection.
The second category of people is “infective” who can pass the contagion to the susceptible and the third group are called “removed” class. These people had the infection and recovered from it and became immune to the virus. The people who died from the infection are also considered in this group. This model clearly shows the significance of isolation for the infected people. That’s why we need a centralized health system to decrease the ratio of isolation and infected people’s numbers.
Exponential explosion of Covid-19
While during January and February this year the contagion was still in control, the latest UK cases of COVID-19 are showing an exponential growth rate of the spread of the virus. According to researchers, such outbreaks eventually pick up pace and then gradually decline as the frequency of contacts decrease.
This is why at the time when there is hardly any infective left and the outbreak is almost over, there will be several susceptibles. By using the S-I-R model we can see an estimate of the ultimate size of the epidemic, or more precisely, the number of people infected at the very end of an outbreak in case there is no remedial action in place.
Fatality Rate
The proportion of the infected cases who die from the disease is considered to be the case fatality rate. Case fatality rate was 50–70% for Ebola patients. As per most realistic estimates the case fatality rate of COVID-19 is somewhere between 0.25% and 3.5%. In this regard, it is crucial to know that the case fatality rate isn’t constant and it can get lower or higher depending on the responses of society and individuals to the contagion and the demographics of the population.
Not quite surprisingly, it has been seen that contagions with high case fatality rates are generally less infectious in nature. Contagions that kill huge numbers of infected people and also spread quickly are almost non-existent except in science fiction. Covid-19 is less fatal but more infectious in nature as a contagious disease.
Checking The Outbreak
Vaccination is regarded to be the most effective measure to check the spread of any contagious disease. Vaccination can take people directly from the susceptible category to the removed category while bypassing the infective state.
At the same time, vaccines only provide us a precautionary measure to curb the outbreaks happening in the first place. But when outbreaks such as the current COVID-19 pandemic are spreading in full swing, vaccines may not be effective to control the disastrous situation.
As more immediate and practical measures, quarantine and isolation are needed to reduce the transmission rate and lower the reproduction of the infection. Isolating infectious patients decreases the rate of spread, while the quarantining measure for healthy people reduces the exposure of the susceptible population to the disease.
Boosting The Immunity of People
Building herd immunity in curbing the spread of a contagious disease is a measure that many governments now focus upon. This idea of creating immunity of people to fight back the virus is something the UK government were thinking about seriously in the early days of the spread of the virus in the country.
The measure has some scientific basis. Basically, herd immunity in regard to the efforts of curbing the disease means that people who have weak immune systems such as the elderly, pregnant women and other high-risk people with health problems can benefit more from the protection created by other people’s immunity.
The effect of herd immunity though depends upon how infectious the disease is.
When a vaccine is released, it can really do great in achieving herd immunity. By vaccinating a high proportion of the population many infectious diseases such as smallpox could be eradicated from human history. But when the vaccine is not available getting infected with the contagion and recovering from it is the only way to develop immunity. But this has the risk of exposing people to the virus causing great fatality. No wonder, no government now is in favour of depending upon herd immunity as a measure until the vaccine is arrived.
Future of Modelling a Contagion Spread
S-I-R model has already been proved effective in dealing with the nitty-gritties of many infectious disease outbreaks. But the model is more effective in case of diseases that cannot be dealt with the building of immunity of the victims. For example
It is too early to judge whether the novel can circulate indefinitely in the population? There are various reports of once infected people catching the virus for a second time. But there is also evidence of COVID-19 patients becoming immune.
The biggest problem as of now with the coronavirus pandemic is that there is a period when an infected person remains asymptomatic. During this period, infected people can transmit the virus and infect others as they show no symptoms. This requires adding another class of people to this model. Still we can decrease the transmission of the virus by using the mobile application for it. The good mobile app development company can help to develop the mobile app with the features like users can check the infected people’s data live on their live location, can do a self assessment online, and also live updates regarding covid 19 can help users to prevent themselves.
Conclusion
All the latest models that are currently being relied upon by experts forming government policies are really complicated. In spite of all these models. As of now predicting the time of curbing the disease largely remained unknown to most of us.
Author Bio: Atman Rathod is the Co-founder at CMARIX TechnoLabs Pvt. Ltd., a leading Android App Development Company with 13+ years of experience. He loves to write about technology, startups, entrepreneurship and business. His creative abilities, academic track record and leadership skills made him one of the key industry influencers as well.
