This study aimed to evaluate the frequency of the main risk factors for severe neonatal hyperbilirubinemia, to determine the incidence of exchange transfusion (ET) in the Autonomous Province of Vojvodina (the northern part of Serbia) and to describe the experience with ET performed in premature and term infants during the past 17 years. We performed a retrospective data analysis of 398 newborn infants who underwent a double volume ET from 1997 to 2013. During the 17 year study period, a decreasing incidence of ET, expressed per thousand newborns, was observed. A total of 468 double volume ET were performed: 328 (82.4 %) infants had one treatment and 70 (17.6 %) had repeated treatments. A total of 262,830 mLs of blood were transfused, an average of 660 mLs per child. There were 221 male and 177 female infants, with a sex ratio 1.25:1. The frequencies of risk factors for developing hyperbilirubinemia were as follows: (1) 38 % RhD incompatibility; (2) 38 % ABO incompatibility (26 % group A infant of group O mother, 12 % group B infant of group O mother); (3) 7 % low birth weight/preterm birth; (4) 17 % other factors. Risk factors for neurotoxicity were identified in 56.3 % of infants. No deaths or complications were reported arising from the treatment. ABO and Rh incompatibilities were found to be the main risk factors for severe neonatal hyperbilirubinemia in Vojvodina. Exchange transfusion, used as therapy for severe hyperbilirubinemia, trended downwards over the period of this study.

Tick-borne encephalitis (TBE), caused by the TBE virus (TBEV), is a life-threatening disease with clinical symptoms ranging from non-specific to severe inflammation of the central nervous system. Despite TBE is a notifiable disease in Serbia since 2004, there is no active TBE surveillance program for the serologic or molecular screening of TBEV infection in humans in the country. This prospective cohort study aimed to assess the TBEV exposure among tick-infested individuals in Serbia during the year 2020. A total of 113 individuals exposed to tick bites were recruited for the study and screened for anti-TBEV antibodies using a commercial indirect fluorescent antibody test (IFA) test. Blood samples from 50 healthy donors not exposed to tick bites were included as a control group. Most of the enrolled patients reported infestations with one tick, being I. ricinus the most frequent tick found in the participants. The TBEV seroprevalence was higher (13.27%, 15 total 113) in tick-infested individuals than in healthy donors (4%, 2 total 50), although the difference was not significant. Notably, male individuals exposed to tick bites showed five times higher relative risk (RR) of being TBEV-seropositive than healthy donors of the same gender (RR= 5.1, CI = 1.6–19; p = 0.007). None of the seropositive individuals developed clinical manifestations of TBE, but the first clinical-stage of Lyme borreliosis (i.e., erythema migrans) was detected in seven of them. Potential TBEV foci were identified in rural areas, mostly in proximity or within the Fruška Gora mountain. We conclude that the Serbian population is at high risk of TBEV exposure. Further epidemiological studies should focus on potential TBEV foci identified in this study. The implementation of active surveillance for TBEV might contribute to evaluating the potential negative impact of TBE in Serbia.

Passive immunotherapy with convalescent COVID-19 plasma (CCP) is used as a therapeutic procedure in many countries, including Serbia. In this study, we analyzed the association between demographic factors, COVID-19 severity and the reactivity of anti-SARS-CoV-2 antibodies (Abs) in Serbian CCP donors. Individuals (n = 468) recovered from confirmed SARS-CoV-2 infection, and who were willing to donate their plasma for passive immunization of COVID-19 patients were enrolled in the study. Plasma samples were tested for the presence of IgG reactive to SARS-CoV-2 spike glycoprotein (S1) and nucleocapsid antigens. Individuals were characterized according to age, gender, comorbidities, COVID-19 severity, ABO blood type and RhD factor. Total of 420 candidates (420/468; 89.74%) reached the levels of anti-SARS-CoV-2 IgG that qualified them for inclusion in CCP donation program. Further statistical analysis showed that male individuals (p = 0.034), older age groups (p < 0.001), existence of hypertension (p = 0.008), and severe COVID-19 (p = 0.000) are linked with higher levels of anti-SARS-CoV-2 Abs. These findings will guide the selection of CCP donors in Serbia. Further studies need to be conducted to assess the neutralization potency and clinical efficiency of CCP collected from Serbian donors with high anti-SARS-CoV-2 IgG reactivity.

Testing neonates and pregnant women contributes to the detection of blood type incompatibility between the mother and her child; it provides an opportunity for clinicians to implement the adequate prevention of RhD alloimmunization as well as to make timely diagnosis and to introduce treatment of hemolytic disease in newborns.

The main goal of pre-transfusion blood compatibility testing is to detect clinically significant antibodies. The provision of antigen negative blood units for those patients is a special challenge for blood establishments. Database with a sufficient number of typed blood donors can help to resolve this problem.