Human Coronavirus OC43 (HCoV-OC43) is a common respiratory virus. It belongs to the family Coronaviridae and is one of several human coronaviruses frequently associated with the common cold. HCoV-OC43 is found globally and infects people of all ages, often peaking during winter and early spring months in temperate climates. This virus is responsible for an estimated 10-30% of all common cold cases.
Understanding OC43 Contagiousness
Human Coronavirus OC43 is contagious and spreads readily. Transmission primarily occurs through respiratory droplets released when an infected person coughs, sneezes, or talks. These droplets can directly enter the mouth, nose, or eyes of another person in close contact.
The virus can also spread through direct contact with an infected individual, such as touching or shaking hands. Indirect contact also plays a role, as the virus can survive on contaminated surfaces. If someone touches a contaminated surface and then touches their eyes, nose, or mouth before washing their hands, they can become infected.
Individuals infected with OC43 are most infectious when experiencing symptoms. However, transmission is possible just before symptoms appear. The incubation period for HCoV-OC43 is short, with symptoms appearing within 2 to 4 days after exposure. Reinfections with HCoV-OC43 are common due to the existence of multiple strains.
Symptoms and Illness Course
Infection with Human Coronavirus OC43 results in mild to moderate upper respiratory tract illnesses, often resembling the common cold. Common symptoms include a runny nose, sore throat, cough, and fever. Individuals may also experience a headache and a general feeling of being unwell.
The symptoms of HCoV-OC43 infection peak around day 3 or 4 of the illness and resolve within about a week. While most cases are mild, HCoV-OC43 can sometimes lead to more severe lower respiratory tract infections, such as bronchitis or pneumonia. These complications are more likely to occur in vulnerable populations, including infants, older adults, and individuals with weakened immune systems or underlying cardiopulmonary conditions. There are no specific antiviral treatments or vaccines currently available for HCoV-OC43; treatment focuses on managing symptoms.
Preventing Transmission
To reduce the spread of Human Coronavirus OC43, several measures can help. Frequent hand washing with soap and water for at least 20 seconds is recommended, especially after being in public places, coughing, sneezing, or blowing your nose. If soap and water are not available, an alcohol-based hand sanitizer containing at least 60% alcohol can be used.
Avoiding touching your eyes, nose, and mouth with unwashed hands helps prevent the transfer of the virus into your body. When coughing or sneezing, cover your mouth and nose to contain respiratory droplets. Staying home when sick also plays an important role in limiting further transmission to others. These practices are effective for reducing the spread of various respiratory viruses.
Distinguishing OC43 from Other Coronaviruses
Human Coronavirus OC43 is one of seven coronaviruses known to infect humans. It is distinct from more recently emerged coronaviruses like SARS-CoV-2, which causes COVID-19, and SARS-CoV, which caused the severe acute respiratory syndrome outbreak. Unlike SARS-CoV-2, which can cause severe illness and high fatality rates, HCoV-OC43 results in mild, cold-like symptoms.
HCoV-OC43 has circulated in humans since around the late 19th century, with molecular analysis suggesting a cross-species transmission event from cattle. Other common human coronaviruses that cause mild upper respiratory illnesses include 229E, NL63, and HKU1. These endemic coronaviruses are widespread, and most people are infected with one or more of them at some point in their lives.