Identification of Respiratory Viruses in Adults: Nasopharyngeal versus Oropharyngeal Sampling

The oropharynx and the nasopharynx are the most common pathways for the introduction of airborne microorganism into the respiratory tract. For these reasons, several methods have been developed over recent decades for the identification of viruses that cause respiratory viral infections at these sites. Although these infections are common in all age groups, the vast majority of studies that have assessed and/or compared the various sampling methods have been conducted with individuals in the pediatric age group (9).

The paucity of this type of study with individuals in the adult population is striking in the light of data indicating that the same sampling methods have lower rates of sensitivity for adults than for children and adolescents (12, 13). Furthermore, different sampling methods can affect the results of laboratory testing. The prevailing view today is that the preferred laboratory technique for viral detection is the nucleic acid amplification test (9). Another important variable is the specific viruses that are compared using the different sampling methods. Most published studies have compared these methods for single viruses and only a minority have looked at all the common respiratory viruses (6, 14, 16).

To address these methodological problems, we designed a NAAT-based study with a large adult population with the aim of comparing the sensitivities of samples from the oropharynx and the nasopharynx for the identification of all respiratory viruses. We also aimed to compare the sensitivity of sampling of the nasopharynx with swabs to the sensitivity of sampling of washings for the same purpose.