A patient presents to their healthcare clinic with fever, chills, muscle pain, cough, and nasal congestion. While this diagnostic dilemma is one of the most commonly encountered for pediatricians and primary care physicians worldwide, it is also quite simple. In the absence of comorbidities, risk factors, or red flags prompting hospitalization, patients are most often sent home with instructions for symptomatic treatment, fluids, rest and proper hygiene to protect their close contacts.
The most common causes of respiratory infections are viruses including rhinovirus, coronavirus, influenza virus, respiratory syncytial virus (RSV), and parainfluenza virus. Notably, a few strains of coronavirus — not the novel coronavirus — are well-known to cause common colds. Typically, it’s not necessary to determine the viral cause in uncomplicated cases because it doesn’t impact management.
That’s not to say that these viruses can’t cause severe disease and death. Influenza virus is a major cause of morbidity and mortality, particularly in the very young and the very old. RSV can cause bronchiolitis requiring hospitalization and oxygen therapy in infants. And each of these viruses can lead to pneumonia, which is associated with a variety of complications and risk of death. Importantly, even in severe cases such as pneumonia, the viral etiology may not change patient care.
It might seem like novel coronavirus is the most common or most important virus to consider in these patients because of all the media attention. However, novel coronavirus is not the most common cause of respiratory infection nor pneumonia. Certainly, in the United States with only 15 cases of novel coronavirus reported as of February 14th, it should only be tested for in patients with pneumonia and exposure history (either travel from China or close contact with a known case). In comparison, as of February 8th, there have been an estimated 26 million cases of influenza virus infection in the United States, with 250,000 hospitalizations and 14,000 deaths. If your patients have not received their 2019-2020 influenza vaccination, remind them it’s not too late.
Remember that adage — when you hear hoofbeats, think horses not zebras? Well, when you have a case of respiratory infection, think first about regionally circulating viruses, not about the one on the news.