Management of chickenpox in pregnant women: an Italian perspective

Development of a one-step diagnostic and differential immunochromatographic method for mpox and chickenpox

OBJECTIVE

Mpox and chickenpox are highly contagious diseases with similar clinical symptoms and co-infection, and diagnostic tests are extremely useful in their differentiation. Mpox virus and chickenpox virus are the main causative pathogens of mpox and chickenpox respectively. This study aims to develop a rapid diagnostic immunochromatographic trip for differential diagnosis of mpox and chickenpox viruses.

METHODS

An immunochromatographic assay (ICA) based on the double-antibody sandwich format was developed. First, the paired monoclonal antibodies (MAbs) were prepared: for mpox, the detecting MAb1 and capture MAb2; for chickenpox, the detecting MAb3 and capture MAb4. These MAbs were against the recombinant antigens (AR/gE) of mpox and chickenpox viruses. Then, the detecting MAbs were conjugated to gold nanoparticles and coated onto the conjugate pads. The capture MAbs were immobilized onto a nitrocellulose membrane at two detection zones to form the Test 1 (T1, to test AR) line and Test 2 (T2, to test gE) line, respectively. Goat anti-mouse IgG antibodies were immobilized onto the nitrocellulose membrane to form the control (C, to verify the effectiveness of the strip) line as the control. Finally, it was assembled into a one-step double T-line colloidal gold immunochromatographic test strip for the differential diagnosis of mpox and chickenpox viruses. The sensitivity, specificity, precision and methodology comparison were evaluated using mpox pseudovirus and clinical samples.

RESULTS

A dual-index ICA strips for the simultaneous detection of mpox and chickenpox were successfully prepared. The sensitivity of the dual-index ICA strips to AR antigen was 0.125 ng/mL, to gE antigen was 0.25 ng/mL, with high specificity, precision and reproducibility. The results can be judged within 10-15 min. Methodology comparison study (PCR vs. ICA strips) of 56 clinical samples found there was no statistically significant difference between the ICA strips and PCR method.

CONCLUSION

The dual-index ICA strips had good sensitivity, specificity, simple procedure and rapid detection. This protocol is very suitable for early diagnosis and differentiation of mpox and chickenpox in medical institutions and individuals.

Seroprevalence Assessment of Anti-Varicella Antibodies among Adults in the Province of Florence (Italy)

Background: Varicella infections follow a benign course in around 90% of cases, with more severe forms occurring in adults. To identify potential pockets of susceptibility and to improve targeted immunization strategies, this study aims to critically assess immunological status by evaluating varicella seroprevalence among adults (18-99 years) in the province of Florence (Italy), nearly a decade after Tuscany introduced the vaccination program. Methods: A convenience sample of 430 subjects aged 18 to 94 years (mean age 51.8 ± 18.8 years), stratified by age and sex (53.7% of subjects were female; N = 231), was collected between 2018 and 2019. Sero-analytical analyses were conducted utilizing EUROIMMUN Anti-VZV ELISA (IgG) kits. Results: Most of them were of Italian nationality (87.4%; N = 376). Among the 430 tested samples, 385 (89.5%) were positive and 39 (9.1%) were negative. The remaining six sera (1.4%), confirmed as equivocal, were excluded from further analysis. No significant differences were found based on sex (p-value = 0.706) or nationality (p-value = 0.112). The application of trend tests (Mantel-Haenszel; Kendall Tau-b) showed a significant trend (p < 0.024 and p < 0.032, respectively), with an increasing probability of finding a positive anti-varicella serological status passing from a lower age group (84.2%) to a higher one (93.0%). By considering the female population aged 18-49 years, the seroprevalence of anti-varicella antibodies was found to be 88.4%, with a susceptibility of 11.6%, highlighting the risk of acquiring infection during pregnancy. Conclusions: The introduction of varicella vaccination has had a significant impact on public health in Tuscany and in Italy more generally. However, further efforts should be made to reduce the number of individuals still susceptible in adulthood, with particular attention given to women of childbearing age and the promotion of vaccination through mass and social media and institutional websites.

Epidemiological Characteristics of Varicella under Different Immunisation Strategies in Suzhou Prefecture, Jiangsu Province

Background: The varicella vaccine is excluded from the Chinese national immunisation programme but is included in the local expanded programme on immunisation (EPI) in the Suzhou Prefecture. This study investigated the epidemiological characteristics of the varicella cases during the implementation of different immunisation strategies in the Suzhou Prefecture, Jiangsu Province. Methods: In this study, we used descriptive statistics. Information on reported instances from 2012 to 2021 was first retrieved. Data on varicella cases were collected from the China Information System for Disease Control and Prevention (CISDCP). Similarly, information on vaccinated children was obtained from the Jiangsu Province Vaccination Integrated Service Management Information System (JPVISMIS). The census data in this study was procured from the Suzhou Bureau of Statistics. Results: From 2012 to 2021, a total of 118,031 cases of varicella were reported in Suzhou, and the average annual reported incidence was 91.35 per 100,000. The average yearly incidence after implementing the two-dose varicella vaccination decreased by 41.57% compared with the implementation of one dose. This study demonstrates two annual incidence peaks, a small peak between April and July and a prominent peak between October and January. It is also possible that this seasonal distribution is related to the geography of Suzhou. The average annual reported incidence between districts with a statistically significant difference (χ2 = 98.077, p < 0.05). The one-dose varicella vaccination coverage gradually increased from 55.34% in 2012 to 89.06% in 2021 and the two-dose varicella vaccination coverage gradually increased from 0.27% in 2012 to 82.17% in 2021. Conclusions: Administering the varicella vaccine in the local EPI has significantly decreased the incidence rate and the total number of cases. A two-dose vaccination schedule is still the best vaccination strategy for varicella vaccine effectiveness.

Seroprevalence of Varicella in Pregnant Women and Newborns in a Region of Colombia

We estimate the seroprevalence of IgG antibodies to varicella zoster virus (VZV) based on the first serological study in a cohort of pregnant women and newborns from the Aburrá Valley (Antioquia-Colombia) who attended delivery in eight randomly chosen hospitals. An indirect enzyme immunoassay was used to determine anti-VZV IgG antibodies. Generalized linear models were constructed to identify variables that modify seropositivity. In pregnant women, seropositivity was 85.8% (95% CI: 83.4-85.9), seronegativity was 12.6% (95% CI: 10.8-14.6), and concordance with umbilical cord titers was 90.0% (95% CI: 89-91). The seropositivity of pregnant women was lower in those who lived in rural areas (IRR: 0.4, 95% CI: 0.2-0.7), belonged to the high socioeconomic status (IRR: 0.4, 95% CI: 0.2-0.7), and had studied 11 years or more (IRR: 0.6, 95% CI: 0.4-0.8). Among newborns, seropositivity was lower in those who weighed less than 3000 g (IRR: 0.8, 95% CI: 0.6-1.0). The high seropositivity and seronegativity pattern indicates the urgent need to design preconception consultation and vaccination reinforcement for women of childbearing age according to their sociodemographic conditions, to prevent infection and complications in the mother and newborn.