Vaccines for Perinatal and Congenital Infections-How Close Are We?

Herpes zoster infection in pregnancy: features and consequences

Herpes (varicella) zoster (HZ) infection occurs in 4 people per 1000 in the general US population (irrespective of prior varicella infection and vaccination status) each year and has been the subject of scientific inquiry for decades. The consequences of infection are myriad and may depend on the dermatome of involvement as well as host factors such as age, comorbidities, prior treatment or immunization, and immunologic status. Pregnancy is associated with an altered immune and hormonal status in the mother. While maternal HZ infection during pregnancy is not uncommon, the implications for both mother and child are not well established, although multiple studies of perinatal maternal HZ infection suggest no intrauterine transmission to the fetus. We review the current literature on herpes zoster infection in pregnancy, including epidemiology, diagnosis, potential immunologic sequelae, and strategies for prevention and treatment.

A review on Zika vaccine development

Zika virus (ZIKV), which belongs to the Flavivirus family, is mainly transmitted via the bite of Aedes mosquitoes. In newborns, ZIKV infection can cause severe symptoms such as microcephaly, while in adults, it can lead to Guillain‒Barré syndrome (GBS). Due to the lack of specific therapeutic methods against ZIKV, the development of a safe and effective vaccine is extremely important. Several potential ZIKV vaccines, such as live attenuated, inactivated, nucleic acid, viral vector, and recombinant subunit vaccines, have demonstrated promising outcomes in clinical trials involving human participants. Therefore, in this review, the recent developmental progress, advantages and disadvantages of these five vaccine types are examined, and practical recommendations for future development are provided.

Systematic review of reverse vaccinology and immunoinformatics data for non-viral sexually transmitted infections

Sexually Transmitted Infections (STIs) are a public health burden rising in developed and developing nations. The World Health Organization estimates nearly 374 million new cases of curable STIs yearly. Global efforts to control their spread have been insufficient in fulfilling their objective. As there is no vaccine for many of these infections, these efforts are focused on education and condom distribution. The development of vaccines for STIs is vital for successfully halting their spread. The field of immunoinformatics is a powerful new tool for vaccine development, allowing for the identification of vaccine candidates within a bacterium's genome and allowing for the design of new genome-based vaccine peptides. The goal of this review was to evaluate the usage of immunoinformatics in research focused on non-viral STIs, identifying fields where research efforts are concentrated. Here we describe gaps in applying these techniques, as in the case of Treponema pallidum and Trichomonas vaginalis.

Acceptance of recommended vaccinations during pregnancy: a cross-sectional study in Southern Italy

Background

Vaccine administration is a recommended, safe, and effective measure to protect pregnant women against vaccine-preventable diseases (VPDs). Despite available guidance, maternal immunization rates for vaccination against influenza and with the reduced antigen content tetanus-diphtheria-acellular pertussis vaccine (Tdap) in Italy remain incredibly low. The primary goal of the study was to explore what Italian pregnant women knew about VPDs and immunization during pregnancy and what factors affected their decision to be vaccinated.

Methods

This cross-sectional study took place between October 2021 and April 2022 in the Southern part of Italy. All consecutive pregnant women, from those attending the selected facilities on randomly selected days, were approached to request participation. The inclusion criteria for participation were age ≥18 years, the ability to understand, speak, and read Italian, and being pregnant at any gestational age. The questionnaire, using a combination of checkboxes and free text answers, consisted of 32 items divided into five parts and lasted ~10 min.

Results

The results showed that 61% knew that the influenza vaccine is recommended and 48.7% knew that influenza could be risky during pregnancy; 74.1% wrongly reported that the Measles-Mumps-Rubella (MMR) vaccine is recommended during pregnancy. Seven out of 10 pregnant women believed that strong evidence supported the safety of vaccinations during pregnancy, and more than half (55.6%) thought they were at increased risk of severe illness with COVID-19. Women in the sample believed that vaccines received during pregnancy pose a risk of adverse events to the unborn child with a median value of 6 (IQR 3-9), on a scale ranging from 1 to 10. Similarly, the fear of contracting pertussis and influenza during pregnancy showed a median value of 6 (IQR 3-9) and 5 (IQR 3-8), respectively. Only 21.1% and 36.5% of women received influenza and Tdap vaccines during pregnancy.

Conclusion

Unrealistic risk perception with a negative attitude toward vaccines in pregnancy and a low percentage of vaccinated pregnant women confirm the urgency of training women to make informed choices to increase overall vaccine uptake.

Safety, Tolerability, and Immunogenicity of V160, a Conditionally Replication-Defective Cytomegalovirus Vaccine, in Healthy Japanese Men in a Randomized, Controlled Phase 1 Study

Cytomegalovirus (CMV) infection can cause newborn morbidity and mortality; no pharmacological method of reducing CMV infection during pregnancy is currently available. In a phase 1 study in the United States, V160, a conditionally replication-defective CMV vaccine, was immunogenic and well tolerated. This placebo-controlled study (NCT03840174) investigated the safety and immunogenicity of a three-dose V160 vaccine administered over six months. A total of 18 healthy adult Japanese males (9 seronegative and 9 seropositive) were enrolled at a single center and randomized 2:1 to intramuscular V160 or placebo. In vitro, V160 induced high CMV-specific neutralizing antibody (NAb) titers (50% neutralization titer [NT50], 3651; 95% confidence interval [CI], 1688-7895) in the CMV-seronegative per-protocol immunogenicity (PPI) population one month after the third vaccine dose was administered compared with no change in the placebo arm (NT50, <94; 95% CI <94-115). The geometric mean titer ratio in the seronegative population versus baseline was 77.7 (95% CI, 23.9-252.4). CMV NAb titers in the CMV-seropositive PPI population were similar to baseline NAb titers observed in the CMV-seropositive population. V160 was well tolerated, and no vaccine viral DNA shedding was observed. In conclusion, the immunogenicity and safety profile of V160 in Japanese participants was consistent with other populations.

In Silico Designed Multi-Epitope Immunogen “Tpme-VAC/LGCM-2022” May Induce Both Cellular and Humoral Immunity against Treponema pallidum Infection

Syphilis, a sexually transmitted infection caused by the spirochete Treponema pallidum, has seen a resurgence over the past years. T. pallidum is capable of early dissemination and immune evasion, and the disease continues to be a global healthcare burden. The purpose of this study was to design a multi-epitope immunogen through an immunoinformatics-based approach. Multi-epitope immunogens constitute carefully selected epitopes belonging to conserved and essential bacterial proteins. Several physico-chemical characteristics, such as antigenicity, allergenicity, and stability, were determined. Further, molecular docking and dynamics simulations were performed, ensuring binding affinity and stability between the immunogen and TLR-2. An in silico cloning was performed using the pET-28a(+) vector and codon adaptation for E. coli. Finally, an in silico immune simulation was performed. The in silico predictions obtained in this work indicate that this construct would be capable of inducing the requisite immune response to elicit protection against T. pallidum. Through this methodology we have designed a promising potential vaccine candidate for syphilis, namely Tpme-VAC/LGCM-2022. However, it is necessary to validate these findings in in vitro and in vivo assays.

Maternal vaccination: a review of current evidence and recommendations

Maternal vaccination is an effective means of protecting pregnant women, their fetuses, and infants from vaccine-preventable infections. Despite the availability of sufficient safety data to support the use of vaccines during pregnancy, maternal immunization remains an underutilized method of disease prevention, often because of concerns from both healthcare providers and pregnant women about vaccine safety. Such concerns have been reflected in the low uptake of the COVID-19 vaccine among pregnant women seen in many parts of the world. Here, we present an update of the current recommendations for the use of vaccines during pregnancy, including the evidence supporting the use of novel vaccine platforms. We also provide an overview of the data supporting the use of COVID-19 vaccines in pregnancy and an update of the status of vaccines that are currently under development for use in pregnant women.

Current development of Zika virus vaccines with special emphasis on virus-like particle technology

Introduction: Zika virus disease received little attention until its recent explosive emergence around the globe. The devastating consequences of this pandemic include congenital Zika syndrome (CZS) and the neurological autoimmune disorder Guillain-Barré syndrome. These potential outcomes prompted massive efforts to understand the course of Zika infection and to develop therapeutic and prophylactic strategies for treatment and prevention of disease.Area covered: Preclinical and clinical data demonstrate that a safe and efficacious vaccine for protection against Zika virus infection is possible in the near future. Nevertheless, significant knowledge gaps regarding the outcome of a mass vaccination strategy exist and must be addressed. Zika virus circulates in flavivirus-endemic regions, an ideal Zika vaccine should avoid the potential of antibody-dependent enhancement from exposure to dengue virus. Prevention of CZS is the primary goal for immunization, and the vaccine must provide protection against intrauterine transmission for use during pregnancy and in women of childbearing age. Ideally, a vaccine should also prevent sexual transmission of the virus through mucosal protection.Expert opinion: This review describes current vaccine approaches against Zika virus with particular attention to the application of virus-like particle (VLP) technology as a strategy for solving the challenges of Zika virus immunization.