Reassessing the Risk of Severe Parvovirus B19 Infection in the Immunocompetent Population: A Call for Vigilance in the Wake of Resurgence

Abstract

Despite Parvovirus B19 (B19V) generally causing mild or asymptomatic infections, and only certain high-risk groups such as hematological or immunocompromised patients and pregnant women tending to develop complications, several factors challenge the assumption of a "benign" clinical course in immunocompetent adults and adolescents. A significant proportion of the population may harbor undiagnosed health conditions or genetic predispositions that could render them more susceptible to severe B19V complications. These could include mild hematological disorders, immune dysregulation not resulting in overt immunodeficiency, or underlying cardiac conditions. Concurrent infections with other pathogens, even seemingly minor ones, could synergistically increase the severity of B19V infection, leading to more pronounced clinical manifestations. While not definitively proven, the possibility of emerging B19V strains with increased virulence or altered tissue tropism cannot be entirely discounted. Additionally, the period of pandemic-related restrictions likely led to reduced B19V circulation, potentially resulting in a cohort of young adults with limited natural immunity, making them more vulnerable to infection. Potential clinical consequences include atypical and severe presentations, even in individuals without known risk factors. The traditional focus on B19V primarily as a pediatric concern might lead to underdiagnosis or delayed diagnosis in adults, potentially hindering timely intervention and management. A surge in B19V-related complications, even if individually mild, could collectively strain healthcare resources, particularly in settings with limited capacity or pre-existing pressures. Possible recommendations are to heighten clinical awareness with a high index of suspicion for B19V infection in adults and adolescents presenting with compatible symptoms, even in the absence of classic risk factors. Additionally, expanding testing criteria and enhancing public health surveillance efforts would be prudent.

Keywords: Parvovirus B19; outbreaks; public health; viral monitoring.

Figure 5

Severe complication of B19V infection reported from 2020 to 2024 in untraditional at-risk groups. Note: * [44,45]; ** [46]; *** [47,48,49,50,51,52,53,54,55,56,57].

Figure 1

Representation of the genomic structure of the B19V genome (ViralZone https://viralzone.expasy.org, accessed on 1 Augst 2024).

Figure 2

Parvovirus B19V IgM positive tests, 2016 to 2024 (* to end June 2024) [26,27].

Figure 3

Absolute number of B19V infections reported annually to the Sentinel Surveillance system during the period from 1 January 1990 to 31 December 2023 in the Netherlands.

Figure 4

Monthly laboratory-confirmed reports of B19V infection in women aged 15 to 44 years in England, from January 2017 to June 2024 [29].