Pooling Saliva Sample as an Effective Strategy for the Systematic CMV Screening of Newborns—A Multicentric Prospective Study

Abstract

Background: Cytomegalovirus is the most common cause of congenital infections worldwide. Screening all newborns in the first 2 weeks of life is the only way to detect all cases of congenital infection, allowing the monitoring of children with asymptomatic infection at birth and early intervention. Aim: In this multicenter study, we aimed to evaluate the feasibility of using a saliva pool strategy for mass screening in 7 Portuguese hospitals, and to estimate the current prevalence of this congenital infection in these hospitals. Methods: A total of 7033 newborns were screened between June 2020 and June 2022, and 704 pools of 10 saliva samples were analyzed by polymerase chain reaction (PCR). Results: Of the 704 pools analyzed, 685 were negative and 19 had positive PCR results for cytomegalovirus. After individual PCR testing, 26 newborns had positive saliva results, of which 15 were confirmed by urine testing. Thus, this study’s prevalence of congenital infection was 0.21% (95% confidence interval: 0.12%–0.35%). Conclusions: In this study, the pooling strategy proved to be effective for the systematic screening of newborns, although this low prevalence raises questions regarding the cost-effectiveness of implementing universal screening. However, this prevalence is probably the result of the control measures taken during the pandemic; therefore, the rates are expected to return to prepandemic values, but only a new study after the pandemic will be able to confirm this.

Implementation of pooled saliva tests for universal screening of cCMV infection

“…A critical consideration with regard to universal screening via sample pooling, refers to the feasibility and logistics and simplicity of operation. A recent study suggested the feasibility of pooling; however, this study included a smaller number of newborn infants (less than half the number of newborn infants screened in the present study), screened over a longer period (2 years), and did not relate to operational considerations 43 . In this study, using our preexistent pooling pipeline, we were able to rapidly incorporate neonatal saliva pooling into routine clinical practice.…”

“…In this regard, a few recent proof-of-concept studies suggested the sensitivity of pooling for cCMV testing, yet they included only a few hundred neonates 39 – 42 . A study in 2023 described the use of pooled saliva testing in 7,033 newborn infants screened for cCMV over a 2-year period 43 . Yet, this study presented limited results, merely describing the feasibility of pooling, with no additional analyses (that is, sensitivity, efficacy and operation).…”