Human Coronavirus 229E (HCoV-229E) is one of several human coronaviruses that commonly circulate globally. It is associated with mild respiratory illnesses, often resembling the common cold.
Understanding Human Coronavirus 229E
HCoV-229E is classified as an alphacoronavirus and is considered one of the four “common cold” coronaviruses, alongside HCoV-OC43, HCoV-NL63, and HCoV-HKU1. These four viruses are responsible for an estimated 15% to 30% of common colds in adults. The virus was first identified in 1965 by researcher Dorothy Hamre at the University of Chicago. In 2024, the species name for HCoV-229E was officially changed to Alphacoronavirus chicagoense.
HCoV-229E is an enveloped, positive-sense, single-stranded RNA virus that enters host cells by binding to the APN receptor. This virus circulates globally, and while it can be detected at various times, it often exhibits increased prevalence during colder months in temperate climates. A study found previous HCoV-229E infection in a significant percentage of young children, with rates of 42.9% to 50.0% in those aged 6-12 months and 65% in children 2.5-3.5 years old.
Symptoms and Transmission
Infection with HCoV-229E presents with mild to moderate upper-respiratory tract symptoms, closely resembling those of the common cold. Common symptoms include a runny nose, headache, sore throat, and a general feeling of being unwell. Some individuals may also experience a mild fever and cough. The incubation period for HCoV-229E is around 2-5 days, with the illness lasting between 2-18 days.
While generally mild, HCoV-229E can sometimes lead to more severe lower respiratory tract illnesses, such as pneumonia or bronchitis. This is more frequently observed in vulnerable populations, including infants, young children, older adults, and individuals with weakened immune systems or underlying cardiopulmonary conditions. There has been at least one published case report of HCoV-229E causing acute respiratory distress syndrome (ARDS) in an otherwise healthy patient without co-infection. The virus is primarily transmitted through respiratory droplets released when an infected person coughs or sneezes. Transmission can also occur through close personal contact, such as touching or shaking hands, or by touching contaminated objects or surfaces and then touching one’s mouth, nose, or eyes.
Diagnosis and Supportive Care
Specific diagnostic testing for HCoV-229E is not routinely performed in clinical practice for most cases, given its commonality and the mild nature of the illness. Diagnosis is often made based on the presence of common respiratory symptoms. However, laboratory tests on respiratory specimens or blood serum may be ordered by healthcare providers, particularly if a patient presents with severe disease or if other more serious coronavirus infections are suspected.
Treatment for HCoV-229E infection is largely supportive, focusing on alleviating symptoms. This involves measures such as getting adequate rest, maintaining hydration, and using over-the-counter medications to manage symptoms like fever or congestion. There are currently no specific antiviral medications approved for treating HCoV-229E infections. Research into potential antiviral compounds has been limited, with some in vitro studies suggesting certain chemicals may have inhibitory effects.
Differentiating HCoV-229E from Other Coronaviruses
HCoV-229E is one of seven coronaviruses known to infect humans, but it is distinct from more severe coronaviruses that have caused widespread outbreaks. These include Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2, which is the cause of COVID-19. Unlike these highly pathogenic viruses, HCoV-229E is not considered a highly virulent pathogen.
The clinical presentation of HCoV-229E differs significantly from the severe acute respiratory infections associated with SARS-CoV, MERS-CoV, and SARS-CoV-2, which can lead to pneumonia, acute respiratory distress syndrome, and multiple organ damage. While SARS-CoV and MERS-CoV have been linked to high mortality rates in past outbreaks, HCoV-229E results in a self-limiting illness.