The immune response is variable among individuals. Yes comorbidities, age, addictions are determinants for sure but the exact trigger factor for the cytokine storm that initiates the lethal cascade of events in covid19 patients needs further evaluation and research.

Agree with dear Sumanta Chakraborty but would like to add physical strength and malnutrition have already approved as major factors too in our study in Iran

Dear Sumanta Chakraborty thanks for the prompt and valued response. I do also believe there is something more that needs to be invented through research.

The main factors are: the patient age + the immune system + the type of Covid 19 (aggressivity).

Thanks Parisa Ziarati for your appreciable contribution. Surprisingly inhabitants of slums in Dhaka city of Bangladesh are less affected where undernutrition is commonly encountered. You may please follow the following link: https://thefinancialexpress.com.bd/views/are-slum-dwellers-immune-to-coronavirus-1596128385

The most common diagnosis in severe COVID-19 patients is severe pneumonia.

The most common symptoms of COVID-19 are fever, tiredness, and dry cough. Some patients may have aches and pains, nasal congestion, runny nose, or sore throat. These symptoms are usually mild and begin gradually.

Most people (about 80%) recover from the disease without needing special treatment, and for the majority – especially for children and young adults – illness due to COVID-19 is generally minor. However, for some people it can cause serious illness.

Thanks Mohamed Farid Benlamnouar for your valued contribution. Your effort is highly appreciable.

Dear Shujaat Ali thanks for your contribution. You have written the clinical manifestations, but here the focus of discussion is why the manifestations are variable in individual to individual? What are the factors that determine the variations in clinical features?

One of the most important determinants of the clinical

manifestations, course and outcome of patients with Covid-19 is the immune status, whether the patient is immunocompetent or immunocompromized. Several circumstances have a profound influence on the immune system including advancing age, frailty, systemic diseases notably diabetes, cardiovascular disease, debilitating disease and renal impairment, malignancy, malnutrition

and drug administration like cytotoxic agents and prolonged corticosteroid therapy.

Thanks Salman K. Ajlan for your excellent contribution.

COVID-19 can affect anyone, and the disease can cause symptoms ranging from mild to very severe. But people with risk factors may be more likely to need hospitalization or intensive care if they have COVID-19, so manifestation depends on the immune status that linked to the risk factors.

According to the WHO, the onset signs and symptoms of COVID-19 are variable.

Most people have fever (83-99%), cough (59-82%), fatigue (44-70%), anorexia (40-84%), shortness of breath (31-40%) and myalgia (11-35%).

Other non-specific symptoms, including sore throat, nasal congestion, headache, diarrhea, nausea and vomiting have also been reported. A loss of smell (anosmia) or taste (ageusia), which precedes the onset of symptoms respiratory, has also been described.

Thanks Manal Hadi Kanaan for your valued contribution. I highly appreciate your effort.

Agree with Manal Hadi Kanaan

Dear Ben Boubakary thanks for your response. You have described the clinical features of COVID-19. But the focus of present discussion is a bit different. I expect a discussion on the factors that determine the variations in clinical features? Thanks for your effort.

Healthy state of patient

Dear Suhad Mohammed thanks for your contribution.

Dear Anmar Aldewachi thanks for your response. You have agreed with the contribution of Manal Hadi Kanaan which is very appreciable.

Agree with Ben

Thanks Mudassir Khan for your response.

Agree with Parisa...

Thanks Emad Kamil Hussein for your interest in the topic and your valued response.

I agree with Dr Salman Ajlan

Thanks Lamia Mustafa Al-Naama and Alaa Hussein Fadhil

The fever and uncomfortable

Dear Suhad Mohammed thanks for your response.