PEM Source

Your source for all things Pediatric Emergency Medicine


Question: ID

(Click the link to comment and to vote – voting not working through email, sorry!)

Which of the following statements related to viral load and rapid antigen testing for common respiratory viruses is true?

pemsou5_wp • January 9, 2024

Previous Post

Next Post


  1. Kelly January 10, 2024 - 12:26 am Reply

    D) FDA-approved rapid influenza tests must be at least 80% sensitive as compared to PCR
    Rapid RSV antigen testing can be useful in high-risk children (neonates, ex-premies, children with chronic heart or lung disease), but bronchiolitis is a clinical diagnosis (that viruses other than RSV cause), and as there is no specific treatment for outpatient RSV disease, testing is not generally needed. Sometimes testing helps clinicians perform fewer other tests, however, particularly for febrile young children. The mnemonic 2-4-6-8, what are the viruses that we hate? can help with peak viral loads. Influenza peaks at ~2 days of symptoms, COVID (now that many have natural or vaccine immunity) at 4 days of symptoms, and RSV at 6-7 days of symptoms. Therefore, to be truly sure one is COVID negative, a final test on day 5-6 of illness is needed. Although swabbing the throat and nose has been suggested to increase the sensitivity of COVID tests, there is not enough evidence to support this practice, and evidence does not support swabbing the throat alone. The COVID vaccine/booster if needed is recommended 3 months after COVID disease, as natural illness-derived immunity will be waning at that time. There are 2 main antigenic subtypes of RSV, and those who have had RSV can get it again within the same season. Therefore, once recovered, RSV vaccine is recommended for those 60yo+. Influenza vaccine covers both H1N1 and H3N2 influenza A and B (quadrivalent), so vaccine is indicated to protect against the other subtypes.

Leave a Reply

Your email address will not be published / Required fields are marked *