Can dengue virus be sexually transmitted?

It has been well documented that Zika virus (ZIKV) can be sexually transmitted. Dengue virus (DENV) shows many similarities with ZIKV; both belong to the genus Flavivirus and share the same main vector route of transmission. Moreover, they share overall architectural features on a molecular level, with a highly similar structure and distinctive insertions, deletions and mutations of their respective E proteins, and it has been suggested that they use a common pathophysiological pathway. In view of similarities with other sexually transmissible viruses, the question arises as to whether DENV could also be sexually transmissible. Limited animal model data do not suggest otherwise. The presence of dengue virus in - and human-to-human, non-vector transmission from - various bodily fluids other than semen or vaginal secretions has been documented anecdotally. Several anecdotal reports described prolonged presence of DENV in semen, urine and vaginal secretions. In 2019, two cases of likely sexual transmission were reported from Spain and South Korea, respectively. We discuss the evidence for and against a relevant DENV sexual transmission potential, highlight controversies and propose a future research agenda on this issue

Rabies antibody response after two intradermal pre-exposure prophylaxis immunizations: An observational cohort study

Background: Rabies is a lethal, but vaccine preventable disease. Vaccination uptake is however hampered by the time-consuming three-dose, 21/28-day schedule. The aim of this study was to examine whether adequate rabies antibody titers are reached after two intradermal (ID) doses of rabies vaccine, with a seven-day window. Method: We conducted an observational cohort study with military personnel. A titer was assessed by RFFIT, on the day of the third vaccination, to ensure an adequate rabies antibody response after ID immunization. Results: After this abbreviated two-dose, seven-day ID schedule, seroconversion was reached in 99.3% (427/430) with a geometric mean titer of 7.59 IU/mL (95% CI 7.04–8.17). Conclusions: Implementation of this two-dose schedule will protect more people against Rabies. Travelers and military personnel under time constraints, who otherwise would remain unvaccinated, can be considered adequately protected after this two-dose schedule. For populations in endemic areas, local application of a two-dose schedule could provide an opportunity to vaccinate more people with less vaccine. Given the paucity of published data, this study adds relevant evidence in support of the new policy (2017) of WHO, concerning a two-dose, seven-day schedule is approved for all healthy individuals

Rabies Antibody Response After Booster Immunization: A Systematic Review and Meta-analysis

Although fatal once symptomatic, rabies is preventable by administration of pre- and post-exposure vaccines. International guidelines suggest lifelong protection by a pre-exposure vaccination scheme followed by timely post-exposure vaccines. Rapidity and magnitude of the antibody recall response after booster inoculation are essential, as many people have been previously immunized a long time ago. The objective of this study was therefore to systematically review the evidence on the boostability of rabies immunization to date. We included 36 studies, of which 19 studies were suitable for meta-analysis. Reduced antibody levels were found after intradermal primary schedules as compared to intramuscular schedules. However, responses after booster immunization were adequate for both routes. Although studies showed that antibody levels decline over time, adequate booster responses were still retained over long time intervals indicating that post-exposure treatment is effective without extra measures after long periods of time

Long-term sequelae of chikungunya virus disease: A systematic review

Background: The acute phase of chikungunya is well documented; less so are its long-term effects. This systematic literature review provides an overview of the currently available data. Methods: We performed an electronic search in PubMed/Medline and checked reference lists. We included studies in English on long-term sequelae of chikungunya in adults and on long-term sequelae of congenital infection from 2000 to 2016. Case reports, reviews and studies with a follow-up shorter than 6 weeks were excluded. Results: In total, 37 studies were included; with follow-up periods ranging from 1.5 to 72 months. Most studies were questionnaire-based studies only, in which clinical diagnoses such as arthritis, alopecia and depression were mostly recorded without professional verification. Persisting arthralgia/arthritis (arthralgia/joint stiffness plus joint swelling) was the most frequent problem encountered. Further frequently mentioned sequelae were alopecia and depression. Quality of life was reduced in many for months to years after the acute phase of chikungunya. Female gender, older age, some co-morbidities and the severity of the acute phase were associated with persistent arthralgia. Congenital infection was associated with neurocognitive dysfunctioning in early childhood. Conclusion: Chikungunya leads to (self-perceived) long-term sequelae in a considerable proportion of patients, impacting significantly on quality of life. Long-term chikungunya sequelae must be taken into account when dealing with this disease because of its important effect on public and individual health. Prospective large-scale, long-term studies with objective assessment of signs and symptoms attributed to the disease are needed to optimally quantify and qualify these problems. (C) 2017 Elsevier Ltd. All rights reserve

Comparison of equivalent fractional vaccine doses delivered by intradermal and intramuscular or subcutaneous routes: A systematic review

Background: For certain vaccines, dosing can be reduced by intradermal (ID) immunization without loss of immunogenicity, as an alternative to standard routes of administration. However, a certain level of dose-sparing might also be achieved by reducing doses of intramuscular (IM) or subcutaneous (SC) vaccines. Method: We conducted a systematic review comparing identical reduced amounts of antigen delivered by either ID, or IM/SC routes (PROSPERO registration no. CRD42020151725). Results: Of 6015 articles identified, we included 26 articles, covering eight different vaccines. Equivalent immune responses were demonstrated in 19/26 studies, and 7/26 studies suggested inferior immune responses after IM/SC immunization. Conclusions: We conclude that fractional dosed IM/SC vaccination is at best as immunogenic, but potentially inferior to ID vaccination. The safety profiles were at large comparable, although minor local adverse events were more common after ID delivery. Future vaccine trials, depending on the platform used, should add a fractional dose IM/SC arm, besides a fractional dose ID arm

Fractional dose of intradermal compared to intramuscular and subcutaneous vaccination - A systematic review and meta-analysis

Background: Vaccine supply shortages are of global concern. We hypothesise that intradermal (ID) immunisation as an alternative to standard routes might augment vaccine supply utilisation without loss of vaccine immunogenicity and efficacy. Methods: We conducted a systematic review and meta-analysis searching Medline, Embase and Web of Science databases. Studies were included if: licensed, currently available vaccines were used; fractional dose of ID was compared to IM or SC immunisation; primary immunisation schedules were evaluated; immunogenicity, safety data and/or cost were reported. We calculated risk differences (RD). Studies were included in meta-analysis if: a pre-defined immune correlate of protection was assessed; WHO-recommend schedules and antigen doses were used in the control group; the same schedule was applied to both ID and control groups (PROSPERO registration no. CRD42020151725). Results: The primary search yielded 5,873 articles, of which 156 articles were included; covering 12 vaccines. Non-inferiority of immunogenicity with 20–60% of antigen used with ID vaccines was demonstrated for influenza (H1N1: RD -0·01; 95% CI -0·02, 0·01; I2 = 55%, H2N3: RD 0·00; 95% CI -0·01, 0·01; I2 = 0%, B: RD -0·00; 95% CI -0·02, 0·01; I2 = 72%), rabies (RD 0·00; 95% CI -0·02, 0·02; I2 = 0%), and hepatitis B vaccines (RD -0·01; 95% CI -0·04, 0·02; I2 = 20%). Clinical trials on the remaining vaccines yielded promising results, but are scarce. Conclusions: There is potential for inoculum/antigen dose-reduction by using ID immunisation as compared to standard routes of administration for some vaccines (e.g. influenza, rabies). When suitable, vaccine trials should include an ID arm

Pre-travel care for immunocompromised and chronically ill travellers: A retrospective study

Background: Immunocompromised and chronically ill travellers (ICCITs) are susceptible to travel related diseases. In ICCITs, pre-travel care regarding vaccinations and prophylactics is complex. We evaluated the protection level by preventive measures in ICCITs by analysing rates of vaccination protection, antibody titres, and the prescription of standby antibiotics. Methods: We analysed, and reported according to STROBE guidelines, pre-travel care data for ICCITs visiting the medical pre-travel clinic at the Academic Medical Centre, The Netherlands from 2011 to 2016. Results: We analysed 2104 visits of 1826 ICCITs. Mean age was 46.6 years and mean travel duration 34.5 days. ICCITs on immunosuppressive treatment (29.7%), HIV (17.2%) or diabetes mellitus (10.2%) comprised the largest groups. Most frequently visited countries were Suriname, Indonesia, and Ghana. Most vaccination rates were >90%. Of travellers in high need of hepatitis A and B protection, 56.6 and 75.7%, underwent titre assessments, respectively. Of ICCITs with a respective indication, 50.6% received a prescription for standby antibiotics. Conclusion: Vaccination rates in our study population were overall comparable to those of healthy travellers studied previously in our centre. However, regarding antibody titre assessments and prescription of standby antibiotics, this study demonstrates that uniform pre-travel guidelines for ICCITs are highly needed. (C) 2017 Elsevier Ltd. All rights reserve

Cystic echinococcosis in sub-Saharan Africa

Cystic echinococcosis is regarded as endemic in sub-Saharan Africa; however, for most countries only scarce data, if any, exist. For most of the continent, information about burden of disease is not available; neither are data for the animal hosts involved in the lifecycle of the parasite, thus making introduction of preventive measures difficult. Available evidence suggests that several species or strains within the Echinococcus granulosus complex are prevalent in sub-Saharan Africa and that these strains might be associated with varying virulence and host preference. Treatment strategies (chemotherapy, percutaneous radiological techniques, but mainly surgery) predominantly target active disease. Prevention strategies encompass anthelmintic treatment of dogs, slaughter hygiene, surveillance, and health-educational measures. Existing data are suggestive of unusual clinical presentations of cystic echinococcosis in some parts of the continent, for which the causes are speculative