Flu does not worsen COVID-19 symptoms

Coinfection with influenza appears to be rare and does not seem to worsen symptoms of the coronavirus disease 2019 (COVID-19), according to a new study.

The COVID-19 outbreak in Wuhan City, China, started in December 2019, coinciding with the flu season.

“To the best of our knowledge, this is the first time that a comparison of the clinical manifestation between the co-infection patients and the patients infected with COVID-19 only,” the researchers said. “It is noted that additional cases and more clinical information will enable making more comprehensive and solid conclusions.”

Of the 115 patients confirmed to have COVID-19, only five were also found to have influenza. Three of these patients had influenza A while two had influenza B. All co-infected patients presented with fever, cough and shortness of breath. [J Med Virol 2020;doi:10.1002/jmv.25781]

Notably, nasal tampon and pharyngalgia occurred in three patients each, suggesting that these may be more specific symptoms that are indicative of such co-infections.

Laboratory results showed that in four patients, lymphocyte levels were reduced relative to the reference range, while concentrations of C-reactive protein (CRP) were elevated. Two patients each had heightened alanine aminotransferase (ALT), aspartate aminotransferase and procalcitonin levels. White blood cell counts, albumin and markers for coagulation function and renal function were all normal.

As pneumonia progressed, four of five co-infected patients showed lymphocyte counts lower than the reference range limit, while neutrophil counts exceeded the upper limit in two patients. At this phase of the disease, ALT was likewise altered in three patients, rising above the upper limit of reference. Albumin, in contrast, dropped to below the reference range in four patients.

The inflammatory marker CRP was elevated all throughout the disease course. Renal function remained normal as the pneumonia progressed.

Complications also arose during progression. One patient developed acute respiratory distress syndrome, which resolved gradually through noninvasive assisted ventilation. Three patients, on the other hand, showed abnormalities in liver function without evidence of jaundice; two patients had episodes of diarrhoea during treatment.

All patients underwent antiviral therapy, including treatment with oseltamivir, supplemented with oxygen inhalation and antibiotic agents. Three required glucocorticoid intervention, and one received transient haemostatic medication.

There were no admissions to the intensive care, and all five patients with co-infections were discharged to their homes without death.

“It is critical to pay attention to the potential co-infection with other respiratory viruses for the COVID-19 infection patients, which effectively helps to prevent the aggravation of disease progression and even the death for patients,” the researchers said.

“We cannot ignore [the fact that] COVID-19 infection might combine with other respiratory viruses, not just influenza virus, to make sure that we could provide the best and the most comprehensive treatment to the patients,” they added.