How serious is Covid-19?
Covid-19 is a highly infectious disease. However, a large proportion of those infected or tested positive either do not develop any symptom or have mild or moderate symptoms. Nearly all people with mild to moderate symptoms recover with supportive care. It can be serious or severe for high-risk populations such as the elderly and those with pre-existing health conditions. However, it is difficult to predict who can develop severe disease. Therefore, everyone should follow preventive measures.
Who is at risk of developing severe illness?
This is not possible to assess with certainty. However, the elderly and anyone with pre-existing health conditions (such as high blood pressure, heart disease, lung disease, cancer or diabetes) appear to develop serious illness more often than others. There is emerging scientific evidence that people with comorbidities are up to twelve times at higher risk of death due to Covid-19 and up to six times more likely to be hospitalised. Men in all age groups are at higher risk than women. Clearly, reducing comorbidities and improving one’s health is key to battling Covid-19. The experience of clinical settings in India indicates that people with two or more comorbidities in any combination, such as diabetes and kidney disease or hypertension and chronic lung disease, are at higher risk of serious diseases. In India, there are an estimated 55 million people with heart diseases and 70 million people with diabetes, which makes all of them high-risk.
Are men at higher risk in comparison to women and if yes, why?
The epidemiological data on Covid-19 cases from different parts of the world as well as India has shown that proportionately more men have tested positive for Covid-19 than women. Of all the Covid-19 deaths in India, 70 per cent of the deaths have been in men. This indicates that men are at a higher risk of suffering from moderate to severe disease. The reasons are not fully understood, and knowledge is evolving. Most likely, it is due to the way in which the immune system of men and women reacts. Researchers have found that in Covid-19, the immune response of men is mostly through cytokines and chemokine (the protective chemicals released by the immune system). The cytokine-based response, while being protective, can be harmful in excess, and results in severe disease, a phenomenon more commonly seen in men. In women, the immune response against Covid-19 is predominantly driven by T-cells. The T-cell-dependent response is more balanced and nuanced. There is more evidence emerging that oestrogen (a hormone in women) may have some protective role against the moderate to severe disease.
There is recent evidence that there could be a post-Covid-19 syndrome in children. How serious is this?
This is still being evaluated. It has been reported from multiple places in the US and is seen in individuals who sort of recovered and then they have a fever, hyper-inflammatory syndrome which affects the skin, intestines, and also results in cardiac dysfunction. Many of these patients require ICU care to support blood pressure. This is a syndrome that has been called multisystem inflammatory syndrome in children (MIS-C) and a case definition has been developed. This is a new disease and knowledge is still evolving. It mimics another similar childhood disease known as the Kawasaki disease.
Can a person be reinfected with Covid-19?
There are not many reports that we can classically categorize under reinfection as of now. To classify any case as reinfection, the genomic sequence of the virus from both episodes should be conducted. There have been only a few such cases of reinfections verified based on genomic sequence out of the 45 million cases reported till the end of October 2020. Based on this information, it is too early to make any conclusive reference. As the pandemic progresses and more and more people recover we may come to know how much of a problem reinfection is.
Does air pollution increase the chance of Covid-19 infection?
There have been studies which have indicated that increased air pollution or PM2.5 level is associated with increase in the morbidity and mortality by 10–17 per cent.2 Pollution causes airway inflammation and predisposes one to infection. More specifically, increase in air pollution results in higher number of cases of chronic respiratory and cardiac diseases such as asthma and chronic bronchitis. These conditions already burden the respiratory and cardiac system of an individual. Thereafter, if a person get Covid-19 infection, it is likely that the already burdened immune system and the inflammation caused by pollution in the system of that individual may not be able to fully handle the disease. Therefore, air pollution is likely to affect the moderate to severe cases of the disease. Studies have reported that the mitigation of air pollution can reduce Covid-19 mortality but can also help in reducing the future mortality.
I keep hearing about mutation in SARS-CoV-2. What does it mean for the severity of disease?
The mutation is a minor change in viral genomic sequence. All viruses mutate which helps them to adapt to continue to infect the human host. SARS-CoV-2 is fairly stable, yet there have been around 15,000 mutations which have been reported till September 2020. But most of these mutations have been in non-significant section of the viruses. There is no evidence that mutations in the various parts of SARS-CoV-2 would alter its ability to cause disease. Current evidence also does not suggest that any significant mutation has occurred to make the vaccines being developed ineffective.
What do we know about the risk of transmission from a confined space?
The study in the journal Science had found that people using long-distance or long-duration shared transport had a high risk of transmission. In fact, this risk was found to be higher than the risk of transmission to those living in the same household. These findings have implications on the use of long-distance mode of travel such as buses and trains.
Are there things I should not do to protect myself from Covid-19?
The key is to follow CABs at all times. A few harmful behaviours like the following should ideally be avoided:
• Smoking (it is the best time to quit smoking).
• Wearing multiple masks (handling of these masks can be challenging and put you at additional risk).
• Taking antibiotics (this is a viral infection, antibiotics do not work).
Is there any special protocol to follow for washing fruits and vegetables?
Wash them thoroughly as you would do otherwise, with clean water. Do not use detergent or other harmful materials on fruits and vegetables. Wash your hands properly after washing fruits and vegetables and avoid touching your face while washing fruits and vegetables.
Can I catch Covid-19 from my pet?
It is a disease transmitted from human-to-human through droplet infection as well as through surface contact. Though there have been a few cases of transmission reported from domestic animals to humans, the details on additional factors are not available for those settings. Studies have found that cats and dogs can get the virus from human beings. Researchers have cautioned against the over-interpretation of these findings. As of now, limited evidence suggests that animals do not contribute to wider spread of infection.
Can Covid-19 be transmitted by houseflies and mosquitoes?
There is no evidence that Covid-19 can be transmitted through houseflies and mosquitoes.
Can Covid-19 spread from shoes?
Evidence available till now indicates that the likelihood of Covid-19 being spread through shoes and then infecting others is low. As a precautionary measure, families with infants and young children should store shoes where children cannot reach them.
Can Covid-19 spread from food? How safe is food ordered from outside?
There is currently no confirmed case of Covid-19 transmitted through food or food packaging. Packaged food and food items are unlikely to transmit the virus. There is no evidence to suggest that Covid-19 is transmitted through food and water. However, considering that the containers we use may hold and transmit the virus to others, it is essential that we remain cautious. Anyone with suspected symptoms like cough and cold should avoid cooking food for others. One should properly clean the surface of the packaged food as a precaution.
Is it safe to receive a courier package?
Yes. Evidence says that the likelihood of an infected person contaminating commercial goods is low. The risk of catching Covid-19 from a package that has moved through, travelled and been exposed to different conditions and temperatures is low. The outer surface of the package should be properly cleaned.
Should one shower after returning from every public place, mall or a hospital?
It is not necessary to shower every time after returning from public places. However, this should be looked at on a case-to-case basis and the risk one poses to family members. If there are high-risk members, it may help to change clothes and take a shower. Every visit to the hospital does not mandate a shower on return but it can be done as a precautionary measure. However, healthcare workers who spend long hours in hospital and potential cases may consider changing clothes and taking a shower on return.
Excerpts from the book, ‘Till We Win’ (Penguin). Dr Chandrakant Lahariya is a medical doctor and leading public policy and health systems expert. Dr Gagandeep Kang is a noted infectious-disease researcher. Dr Randeep Guleria is director of the All India Institute of Medical Sciences, New Delhi. The authors have made an attempt to cite the most updated and reliable sources including peer-reviewed medical journals.
