Covid-19 is an acronym of coronavirus disease 2019. Coronaviruses are a large family of viruses that are common throughout the world. They can cause respiratory illness in people and animals. This particular one originated in China at the end of 2019 in the city of Wuhan. In the past two decades, coronavirus outbreaks have caused global concern, including one in 2003 with the Severe Acute Respiratory Syndrome (SARS) and more recently in 2012 with the Middle East Respiratory Syndrome (MERS).
Covid-19 is a disease caused by SARS-CoV-2 that can trigger what doctors call a respiratory tract infection. It can affect the upper respiratory tract, viz. sinuses, nose, and throat or lower respiratory tract, viz. windpipe, and lungs. Severe cases can lead to serious respiratory disease, and even pneumonia.
On January 30, 2020, the WHO declared the Covid-19 outbreak a global health emergency. On March 11, 2020, the WHO declared it a global pandemic.
Risk factors –
The following are the risk factors that are likely to predispose the people to Covid-19 infection –
Age 65 years and older –
People, who are 65 years and older, are at a higher risk of Covid-19 infection due to their decreased immunity. They are more likely to have some associated co-morbidities like diabetes, hypertension, chronic kidney disease, and chronic obstructive pulmonary disease. Also, the course of disease tends to be more severe in them resulting in higher mortality. However, its transmission among the elderly population can be reduced by taking appropriate preventive measures.
Chronic lung disease and asthma –
People with asthma are more likely to catch Covid-19. The hospital data shows that respiratory patients are more likely to experience severe complications. As there is still no cure for it, the best action that people can take is to protect themselves from infection. The same is the case with other chronic lung diseases.
Serious heart conditions –
Covid-19 causes direct damage to the lungs and triggers an inflammatory response, which places stress on the cardiovascular system in two ways, viz. by infecting the lungs the blood oxygen levels drop and the inflammatory effects of the virus itself cause the blood pressure to drop as well. In such cases, the heart must beat faster and harder to supply oxygen to major organs.
According to the European Society of Cardiology, individuals with heart conditions such as heart failure, dilated cardiomyopathy, advanced forms of arrhythmogenic right ventricular cardiomyopathy, and patients with congenital cyanotic heart disease are at the highest risk.
Severe obesity –
There are increasing number of reports that have linked obesity to more severe Covid-19 infection and death. Obesity reduces the protective cardio-respiratory reserves and weakens the immune regulation that appears likely to help the progression to critical stage of the disease.
Researchers found that among individuals with Covid-19 aged less than 60 years in New York City, those with a BMI between 30-34 Kg/m2 and greater than 35 Kg/m2 were 1.8 times and 3.6 times more likely to be admitted to critical care respectively than individuals with a BMI lesser than 30 Kg/m2.
A new study published in 2020 in Diabetes Care concluded that patients with Covid-19 are two and a half times more likely to have severe pneumonia if they are obese than if they are not. Obesity brings with itself a chronic inflammatory state. Whether obesity is an independent risk factor for susceptibility to infection requires further research.
Diabetes is a risk factor for hospitalization and mortality of the Covid-19 infection. Diabetics have impaired immune response to infection concerning cytokine profile and changes in immune-responses including T-cell and macrophage activation. Poor glycemic control impairs several aspects of the immune response to viral infection and also to the potential bacterial secondary infection in the lungs. Poor glycemic control is a risk factor for Covid-19 infection and its adverse outcomes. Hence the importance of tight glycemic control in diabetics cannot be overlooked.
Chronic kidney disease –
People with chronic kidney disease are at an increased risk of the infection. People on dialysis can have weaker immune systems, making it harder to fight infections. Nonetheless, the kidney patients need to continue with their regularly scheduled dialysis treatments and to take necessary precautions as recommended by their healthcare provider.
People with a kidney transplant need to take anti-rejection medicines, also known as immunosuppressive medicines, which keep the immune system less active.
Liver disease –
All patients with liver disease are at risk of adverse outcomes from the virus. Also, some people with certain liver conditions are extremely vulnerable. They include people on immune-suppression for a liver transplant or for autoimmune hepatitis (AIH) and people with liver cancer who are undergoing active chemotherapy.
Immune-compromised people –
A person of any age group can become immune-compromised. The conditions that can cause a person to be immune-compromised include cancer treatment, smoking, bone marrow or organ transplantation, immune deficiencies, poorly controlled AIDS, and prolonged use of corticosteroids and other immune weakening medications.
There are reports that, in some Covid-19 patients, death has occurred probably due to a cytokine storm, when the immune system goes into overdrive, thereby damaging even healthy tissue that may lead to multiple organ failure, sepsis, and even death.