5 Best of 2017: Pediatrics Viewpoints

William T. Basco, Jr., MD


December 28, 2017

In This Article

Can We Place Our Trust in 'Overt Viral Features'?

It can be difficult to differentiate between viral and bacterial pharyngitis caused by group A Streptococcus (GAS), in part because of significant overlap in the symptoms and physical findings between these two entities. Current recommendations are that clinicians should avoid the sequence of rapid antigen testing followed by throat culture for all antigen-negative tests in patients with overt viral features such as rhinorrhea, cough, oral ulcers or vesicles, conjunctivitis, stomatitis, or hoarseness. The rationale for this recommendation is that as many as 1 in 5 children carry oropharyngeal GAS, so testing all children with viral features and pharyngitis symptoms will identify GAS pharyngeal colonization rather than true GAS pharyngitis.

This study[3] assessed a cohort of children tested for GAS pharyngitis to determine the proportion of children who had overt viral features with true GAS pharyngitis. Participants were 3-21 years old. All children presented with sore throat, and a rapid antigen test was conducted at point of care; negative rapid results were confirmed by culture. Attending clinicians documented specific symptoms and physical findings as part of the research protocol.

There were 320 total participants, and about one third (35%) of the children were febrile upon evaluation. A rapid antigen test was obtained in 28% of the children, 6% of whom had a positive bacterial culture after a negative rapid antigen test. Overt viral features were common, with 49% of all children reporting cough and 40% experiencing rhinorrhea. Only 4% had evidence of oral ulcers or vesicles, and only 2% exhibited conjunctival injection. Just over a third (37%) of the children presented with no viral features; a slightly smaller percentage (30%) had two or more features.

GAS was present in 34% of the overall sample. An inverse correlation was demonstrated between overt viral features and GAS status, and there was a statistically significant trend toward decreased GAS prevalence as the number of viral features increased. The prevalence of GAS pharyngitis in patients without viral features (42%) was higher than in patients with viral features (29%; P = .01). Some viral features were present in large proportions of both GAS-positive and GAS-negative children. For example, cough was present in 51% of the GAS-negative children and 43% of the GAS-positive children. Similarly, rhinorrhea was present in 44% of the GAS-negative children and 30% of the GAS-positive children.

The study authors concluded that the number of viral features was associated with GAS status. Furthermore, they urge additional investigation with larger datasets collected in varied settings to determine whether clinicians can identify a population of patients with pharyngitis who should not undergo GAS testing.


In re-evaluating this study several months after initially writing about it, I am still concerned that 23% of the children with symptoms of pharyngitis who exhibited two or more viral symptoms were still positive for GAS. In some populations, that percentage is identical to the carrier rate, raising the question of whether we are merely detecting carriers among those with multiple viral features. However, there's no way to connect those dots in this study. So, although the study raises intriguing questions and provides interesting data to show that the chance of identifying GAS in children exhibiting several features of viral illness is low, the number with GAS is still significant and bears consideration. The problem with interpreting what this study indicates for practice is complicated by the fact that rheumatic fever, the outcome that we seek to avoid by treating GAS pharyngitis, is relatively uncommon, so "proving" that the 23% positive rate for GAS among children with multiple viral features represent carriers who would not benefit from antibiotics is really difficult. The current guidelines for diagnosis and treatment of GAS are available online.


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