The lack of routine surveillance of Parvovirus B19 infection in pregnancy prevents an accurate understanding of this regular cause of fetal loss and the risks posed by occupational exposure

Abstract

In Europe, fetal loss due to Parvovirus B19 (B19V) is under-reported and a poorly addressed occupational risk to pregnant women. This is exemplified internationally, where it was unmentioned in the last two European Centre for Disease Prevention and Control (ECDC) annual surveillance reports or its 2009 special report on infections in pregnancy. To assess this potential for underestimating B19V fetal loss in pregnancy, we undertook a systematic review of practice in Northern Ireland in the management and reporting of B19V infections over a 12-month period of heightened transmission, one of six observed in a span of 9 years. Pregnant and non-pregnant women presented with symptomatic infection in 24 and 93 % of confirmed B19V infections, respectively, with no difference in viral loads. There was underinvestigation of viral causes of fetal loss, with only 143/2739 (5 %) tested for B19V, and a failure to follow up most non-immune women tested following rash contact. Occupational exposure was recorded in 31/60 (51.6 %) of pregnancies audited following rash exposure, the majority teachers or day care workers. Against a background seroprevalence of 66.5 % immunity in women of child-bearing years, two patterns of infection were identified. Firstly, pregnant women investigated for a rash or exposure to slapped cheek syndrome, where an infection incidence of 18 % was observed, resulted in 42 confirmed infections, all proceeding to healthy term deliveries. Secondly, pregnant women with unsuspected infection had six cases of confirmed B19V fetal loss, including four of 22 (18 %) diagnosed at autopsy, of which three were non-hydropic. While many studies have reported B19V fetal loss in pregnancy, there are no robust public health surveillance figures to draw on. That all six confirmed fetal losses came from the small number of miscarriages/stillbirths investigated, 143 out of 2739, suggests inadequate follow-up of those pregnancies where B19V-related fetal loss may be most common, and supports the need for enhanced surveillance pilots to address this significant gap in public health knowledge.

Increased number of parvovirus B19 infections in southeast Scotland in 2012–2013

“…The number of acute B19V infections in pregnant women was very high in comparison to the previous five years where fewer than five cases were described annually (Fig. 1, Table 2) and also in comparison with previous reports from Marseille and Belfast [11,12]. This is despite the fact that the annual number of B19V tests has remained relatively constant (i.e.…”

“…Furthermore, a 7% seroconversion rate was recorded in non-immune pregnant women who were re-tested after exposure. As reported previously [12], there was a clear difference in the reason for testing pregnant women and non-pregnant women or men; pregnant women were tested because of exposure to suspected B19V infection (or rash) and most of them remained asymptomatic (95%), in contrast non-pregnant women and men were typically tested because they presented with clinical symptoms (90%). Hence awareness of the asymptomatic nature of B19V infections during pregnancy is important for healthcare workers managing these individuals, especially in B19V endemic years.…”

Human Parvoviruses

“…It has been argued that lack of surveillance and virological investigations led to inaccurate estimates of fetal loss and associated risk factors such as maternal environmental contacts (528,529). Of note, B19V infection may be without symptoms in an expectant mother, and fetal loss secondary to B19V might not be suspected except by the interested specialist (487,530,531).…”

Parvovirus B19 Achievements and Challenges

“…Several studies have been carried out to obtain an experimental evaluation of the impact of B19V infection on prenatal pathologies, although with discordant results [297][298][299][300][301]. A major problem arises with the heterogeneity of the diagnostic procedures employed by different groups and, therefore, of the criteria used to include subjects in the study groups.…”