Immunological considerations and vaccines against COVID-19

The outbreak COVID-19 is considered as a revolution in history of biological science. SARS-CoV-2 is a main cause of COVID-19 having resemblance with MERS-CoV and SARS-CoV. The response of host to the infection of SARS-CoV is multiform and strong. Initially, an effective host defense in the lung is affiliated with disease resolution and mild symptoms. The escaping of virus from immune response can lead to damage the alveoli, systematic inflammation, and ineffective lung repair mechanism with associated organ dysfunction. The immunological responses are necessary to fight with the virus and an effective and a safe vaccine is needed to overcome the pandemic. The development of vaccine is progressing fast, billions of dollars committed with more than 200 candidates before even knowing whether a vaccine candidate will succeed.