A politician from Idukki who was tested positive for coronavirus got discharged from hospital in eight days. He was admitted in the hospital on March 26 and discharged on recovery on April 3. A techie working at Google in Bengaluru, who was returning from his honeymoon, also tested positive for coronavirus, and was discharged from the hospital in eight days. He was admitted on March 11 on suspicion, and tested positive on March 12. On March 19, after his tests returned negative, he was sent home and was asked to be in home isolation for 28 days.
However, a family of three in Pathanamthitta who tested positive for the virus upon returning from Italy, took almost an entire month to recover. They had been admitted in the hospital on March 6 and discharged on March 31.
So why do different people recover from the coronavirus disease at such different rates? TNM spoke to experts to understand why recovery time varies from person to person.
“The virus is an invading agent and we are the host, the host-virus interactions have a huge range of possibilities and are not the same for everybody. For every disease - virus or bacterial there is a host pathogen interaction,” explains Dr Jacob John, former head of the Indian Council for Medical Research (ICMR), Centre for Advanced Research and emeritus professor at the Christian Medical College (CMC) in Vellore.
In simple words, not every person's immune system reacts to the virus in the same manner. Every disease caused by a microbe, whether a virus or bacteria, does elicit some response from the immune system, but the time for the response to occur may vary from person to person.
Three determining factors
According to Dr Vinay Devraj, Consultant - Infectious Diseases at Apollo Hospitals in Bengaluru, there are three factors that determine the time taken by a patient to recover -- The virus, the host (the patient) and the environment. As far as India is concerned, the third factor is not so important.
The virulence of the virus is one of the major factors. The more aggressive the virus is, the more intense the infection will be in an individual. The extent of the virulence is not in our control however.
Second major factor is the immunity of the host, which is the patient. If the patient has a strong immune response, then their system will be able to fight off the viruses and save itself from shutting down. A strong immune system however does not guarantee complete recovery. Sometimes when the immune system responds strongly to the virus, the body might not be able to deal with the response and it might lead to catastrophic consequences. On the other hand, when the patient has a weak immune system due to conditions like severe diabetes or HIV or cancer treatment, then the virus will again overpower the system and take over the body function, affecting all the essential organs.
The third factor also plays a small role in the sense that how early the infection is detected and how early the patient seeks medical help also affects the time taken to recover.
So how does the immune system normally respond to an infection?
The coronavirus is transmitted via the respiratory system. It spreads through coughing, sneezing and speaking and settles in the upper nasal cavity and throat tissues, where it begins to infect other cells and spread.
The immune system is made up of different types of white blood cells which help fight off infections, of which B cells have the ability to form specific antibodies against an invading organism.
The immune system’s cells are activated and the immune response occurs to fight off the infection.
According to Dr Jacob, this immune response interaction has three elements to it, which determine how quickly an individual recovers from the infection. The first is when the immune system has managed to begin fighting off the invading virus, which is then shed. The second is to look at how the virus sheds; some organisms shed via secretions such as mucus/phlegm, while others are shed in feces or urine.
“Lastly, we have to look at whether the shedding of virulent products poses a risk to another individual,” he adds.
If someone is suspected to have COVID-19, the incubation period - that is the time it takes for the body to recognise there has been an infection- then it becomes known when that person can potentially transmit the infection. For COVID-19 symptoms to occur this time varies anywhere from a few days to a couple of weeks.
Dr Amar Fettle, state nodal officer of COVID-19, also stresses on the agent, host and environment triangle which acts in different ways for different patients.
“All viral infections are like this. There is an agent host environment that makes the recovery different for all diseases; it would take longer for some people and less for others. The triangle also determines the magnitude of the infection as well. This depends on these factors which are independently variable then there is a question of how variable it can become,” he says.
While the general symptoms of manifestation of a disease may be similar, the time for the symptoms of the infection to show will vary between two individuals. He explains that this depends on the 'triangle of causation' - a concept of epidemiology which helps to determine how an infectious disease will manifest in a community.
Peculiar features of virus
Every microbe, whether virus bacteria or otherwise, has its own specific details and features.
“The common cold is a respiratory infection that causes inconvenience but there is no fatal pathology. The virus is shed in secretions such as when one sneezes. Pregnant women have fairly high mortality with H1N1, but no problem with H3N2 and swine flu and avian flu,” says Dr Jacob of the nature of viruses.
“The peculiarity of coronavirus is that while it spreads as easily as the flu, the disease it causes is ten times more aggressive than the flu. When a newer strain of a virus is introduced into a community, the chances of people having immunity against it are less, so it spreads rapidly at first, however most individuals survive because the mortality rate of the virus is generally low. This is what causes the curve to go down, because then by extension 99 percent of the community is immune to the disease,” he adds.
Supportive Care is Crucial
Dr Amar further says that giving supportive care is crucial apart from maintaining general wellbeing.
While the government provides the supportive care, maintaining the wellbeing of one’s mind and body is each individual’s responsibility.
“Maintaining general health and emotional well- being is extremely important for fighting viral infection and therefore the body needs to be empowered for that. Hence we keep telling people to have leafy vegetables, fruits, to drink a lot of water, to have enough sleep, to stay happy, to do exercise,” he says.
Inputs: Nimeshika Jayachandran and Megha Kaveri