According to the Alabama Department of Public health,human coronaviruses are common throughout the world and were first identified in the mid-1960s. Seven different coronaviruses, that scientists know of, can infect people and make them sick.
Common human coronaviruses, including types 229E, NL63, OC43, and HKU1, usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. Most people get infected with these viruses at some point in their lives. These illnesses usually only last for a short amount of time. Human coronaviruses can sometimes cause lower-respiratory tract illnesses, such as pneumonia or bronchitis. This is more common in people with cardiopulmonary disease, people with weakened immune systems, infants, and older adults.
Two other human coronaviruses, MERS-CoV and SARS-CoV, have been known to frequently cause severe symptoms. MERS symptoms usually include fever, cough, and shortness of breath which often progress to pneumonia. About 3 or 4 out of every 10 patients reported with MERS have died. MERS cases continue to occur, primarily in the Arabian Peninsula. SARS symptoms often included fever, chills, and body aches which usually progressed to pneumonia. No human cases of SARS have been reported anywhere in the world since 2004. In December 2019, a new (or novel) human coronavirus (SARS-CoV-2) type emerged in China.
Most people will have mild effects from the virus, but it can cause severe illness and pneumonia in others. Symptoms may appear 2-14 days after exposure to the virus. It is not unusual for symptoms to worsen the second or third week after improving or going away. People with these symptoms may have COVID-19 (SARS-CoV-2) :
According to the Alabama Department of Public Health, thenovel H1N1 (referred to as “swine flu” early on) is an influenza virus causing illness in people. This virus was first detected in people in the United States in April 2009. This virus is spread from person to person, much like the seasonal influenza viruses spread. Most U.S. cases have not been severe and are comparable to seasonal influenza. Information on disease severity and the extent of community spread indicates individual school closure is not a necessary control measure.