Non-Communicable Disease and Healthcare System Developments
EMA Pharmacovigilance: Cenobamate Hepatotoxicity Warning
The EMA’s Pharmacovigilance Risk Assessment Committee (PRAC) has agreed on a direct healthcare professional communication (DHPC) for cenobamate (Ontozry), an anti-seizure medication used as adjunctive therapy for focal-onset epilepsy in adults refractory to at least two prior treatments. The communication follows the identification of cases of severe liver injury with hepatic failure in patients receiving the medicine, with the majority of cases occurring in the context of polypharmacy with other anti-seizure agents. PRAC has recommended adding hepatic injury as a rare adverse effect—defined as occurring in up to 1 in 1,000 patients—alongside new mandatory guidance for baseline and on-treatment liver function monitoring. Prescribers are advised to perform liver function tests before initiating cenobamate and at regular intervals during treatment, and to promptly evaluate any patient presenting with symptoms potentially indicative of hepatocellular injury, including fatigue, anorexia, right upper quadrant discomfort, dark urine, or jaundice. Dose reduction or discontinuation should be considered if hepatotoxicity is confirmed, with abrupt cessation avoided to minimise the risk of rebound seizures. The DHPC will be forwarded to the CHMP for adoption before dissemination by the marketing authorisation holder. Elevated liver enzyme levels were already listed as a common adverse effect in Ontozry’s product information; this update constitutes an upgrade in the severity characterisation and introduces formal hepatic monitoring requirements.
Clopidogrel versus Aspirin After Percutaneous Coronary Intervention: Ten-Year Data
The HOST-EXAM extended follow-up, published in The Lancet (Volume 407, Issue 10537), provides the most methodologically robust long-term comparative data on antiplatelet monotherapy after percutaneous coronary intervention (PCI). Among 5,438 patients who had completed dual antiplatelet therapy (DAPT) without clinical events and were randomised to clopidogrel 75 mg or aspirin 100 mg once daily, the median follow-up reached 10.5 years. Clopidogrel was associated with a statistically significant reduction in the primary composite endpoint of all-cause death, non-fatal myocardial infarction, stroke, readmission for acute coronary syndrome, and BARC type ≥3 bleeding (Kaplan–Meier estimate 25.4% versus 28.5%; HR 0.86, 95% CI 0.77–0.96). Both the thrombotic (17.3% versus 20.0%) and bleeding (9.1% versus 10.8%) components of the composite endpoint were individually lower in the clopidogrel group, while all-cause mortality was similar between arms. Notably, the randomised antiplatelet strategy was mandated only through the initial 24-month follow-up, with subsequent therapy at physician discretion; the sustained benefit observed at ten years thus reflects the durability of the early treatment advantage rather than sustained protocol adherence. These findings reinforce consideration of clopidogrel as a preferred agent for chronic-phase antiplatelet monotherapy following PCI—a recommendation with direct clinical relevance in a Bulgarian population that carries a substantial burden of coronary artery disease and where aspirin has historically predominated as the default maintenance therapy.
Next-Generation Yellow Fever Vaccine: Phase 2 Non-Inferiority Data
A phase 2 randomised observer-blinded active-controlled trial published in the New England Journal of Medicine (Volume 394, Issue 14) evaluated the immunogenicity and safety of vYF, a next-generation live-attenuated yellow fever vaccine produced in Vero cells, compared with the licensed reference vaccine YF-VAX. Among 485 participants included in the per-protocol non-inferiority analysis (329 vYF; 156 YF-VAX), seroconversion by day 29 occurred in 99.7% and 99.4% of recipients respectively (difference 0.3 percentage points; 95% CI –1.2 to 3.2), meeting the pre-specified non-inferiority criterion of −5 percentage points. Neutralising antibody geometric mean titres were comparable across the two vaccine groups at all measured timepoints. Safety profiles were similarly matched, with solicited adverse events reported in 56.7% of vYF recipients and 61.1% of YF-VAX recipients, and no major safety signals identified. The development of a Vero cell-derived yellow fever vaccine addresses supply chain vulnerabilities inherent in the existing embryonated-egg production platform, which has experienced periodic shortages in response to outbreak demand. If these findings translate to licensure, vYF would expand global yellow fever vaccine production capacity—a significant public health benefit given the ongoing enzootic burden in sub-Saharan Africa and tropical South America.
Infectious Diseases: Global Perspective
Respiratory and Droplet Transmission
Avian Influenza A(H7N7) — Taiwan
On 3 April 2026, Taiwan CDC reported a confirmed human case of avian influenza A(H7N7) infection—the first reported case globally since 2013, when three mild cases were documented in Italy following a poultry outbreak in Emilia-Romagna. The patient, a man in his 70s with underlying chronic diseases, developed rhinorrhea, myalgia, and cough on 20 March 2026 and was hospitalised on 22 March with pneumonia. Genomic analysis of sputum samples confirmed A(H7N7) belonging to the Eurasian lineage, closely related to strains circulating in wild waterfowl (predominantly geese and ducks) in Taiwan. The patient had documented exposure to domestic birds prior to symptom onset. No mutations associated with enhanced human-to-human transmissibility or antiviral resistance were detected, and the patient received antiviral treatment before being discharged on 3 April. Of 33 identified contacts monitored, six family members tested negative; three contacts received oseltamivir prophylaxis. Environmental sampling from the index farm returned negative results, with sampling of neighbouring farms ongoing.
Avian influenza A(H7N7) has a well-characterised history in the EU/EEA: the 2003 Netherlands outbreak affected 89 individuals, predominantly with conjunctivitis and mild influenza-like illness, with one fatal case involving pneumonia and acute respiratory distress syndrome. ECDC’s risk assessment for the general population in the EU/EEA remains low, consistent with the absence of human-to-human transmission and the lack of mammalian adaptation markers. The thirteen-year interval since the last human case underscores the sporadic and occupationally concentrated nature of A(H7N7) human infection; however, the pathogen’s continued circulation in wild bird reservoirs maintains a persistent zoonotic hazard for those with occupational or recreational exposure to infected animals.
Avian Influenza A(H9N2) — Italy (Imported from Senegal)
On 21 March 2026, Italy’s National IHR Focal Point notified WHO of a confirmed human case of avian influenza A(H9N2) in an adult male who had resided in Senegal for more than six months before returning to Italy in mid-March. This case is epidemiologically significant as the first imported human case of A(H9N2) ever reported in the European Region. The patient presented to an emergency department with fever and persistent cough; bronchoalveolar lavage performed on 16 March simultaneously identified Mycobacterium tuberculosis and an un-subtypeable influenza A virus. The patient was managed under airborne precautions and treated with both anti-tuberculosis therapy and oseltamivir; his condition was stable and improving as of 9 April. Next-generation sequencing performed at a regional reference laboratory confirmed influenza A(H9N2), with subsequent characterisation at Italy’s National Influenza Center demonstrating close genetic similarity to A(H9N2) strains previously identified in Senegalese poultry. No direct exposure to poultry, wildlife, or symptomatic human cases was identified during epidemiological investigation, though A(H9N2) is enzootic in poultry and environmental samples at live bird markets in Senegal, making indirect environmental exposure a plausible transmission route. All identified contacts in Italy tested negative and completed active monitoring and quarantine; contacts identified in Senegal were asymptomatic.
In epidemiological context, the majority of previously reported human A(H9N2) cases have been documented in China, predominantly among young children with mild respiratory illness following poultry exposure. WHO’s risk assessment characterises the current risk to the general population as low, noting the absence of evidence for sustained human-to-human transmission across all characterised A(H9N2) strains. Nevertheless, the detection of an imported case in Europe highlights both the interconnectedness of the African poultry reservoir with European health systems through human travel and the importance of maintaining IHR notification mechanisms and One Health surveillance frameworks for novel influenza subtypes.
Vector-Borne Transmission
Dengue — New Caledonia
New Caledonia is experiencing its first dengue epidemic since 2019, with over 640 probable and confirmed cases reported through the beginning of April 2026. The primary vector, Aedes aegypti, drives transmission dynamics that typically peak during the warm and wet austral summer season extending into early autumn (March–April), corresponding precisely with the current outbreak period. A notable feature of this outbreak is the apparent partial protective effect of a large-scale Wolbachia biocontrol programme initiated in 2019: by 2024, 86% of Aedes aegypti sampled in the Greater Nouméa region carried Wolbachia bacteria, which impairs dengue virus replication within the mosquito. Consistent with this, authorities report less intense transmission in Wolbachia-release zones relative to other areas of the territory. Ongoing school holidays from 4 to 19 April are expected to facilitate population movement within and between districts, with potential for geographic spread of the outbreak.
ECDC’s risk assessment classifies the risk of dengue infection for travellers to New Caledonia as moderate, particularly for those travelling outside the Greater Nouméa region. The likelihood of autochthonous transmission in mainland Europe following importation by a viraemic traveller is considered very low at this time of year, given that environmental conditions do not currently support Aedes mosquito activity. Clinicians in Bulgaria and across the EU/EEA should nonetheless consider dengue in the differential diagnosis of returning travellers from New Caledonia presenting with compatible febrile illness, and travel medicine services should pre-emptively counsel prospective travellers to the territory.
Infectious Diseases: European Union/European Economic Area
Respiratory and Droplet Transmission
Respiratory Virus Activity: End-of-Season Transition
According to the ECDC Communicable Disease Threats Report for Week 15 (4–10 April 2026), respiratory virus activity across the EU/EEA has returned to inter-seasonal baseline levels. Primary care consultation rates for influenza-like illness and acute respiratory infection are at baseline in the majority of reporting countries, with the pooled ILI/ARI test positivity for influenza in primary care declining to 2% (IQR 0–2.8%), down from 20 reporting countries in Week 13. Influenza intensity is classified as baseline in 11 of 17 reporting countries, with five at low intensity and one at medium; geographic spread has similarly de-escalated, with 8 of 16 countries reporting only sporadic influenza detections. Influenza A remains dominant over the season, with subtype A(H3) accounting for approximately 59% of genetically characterised specimens and subclade 2a.3a.1(K) comprising 90% within the A(H3) grouping. A(H1)pdm09 represented 40% of typed specimens, predominantly subclade 5a.2a.1(D.3.1).
RSV activity and associated hospitalisation rates, while declining, remain elevated relative to baseline. The pooled hospital test positivity for RSV in Week 14 was 11% (IQR 7–13%), with RSV-B accounting for 67% of subtyped hospital specimens. Children under five years of age continue to represent the predominant hospitalised population. SARS-CoV-2 circulation remains low across all age groups, with a pooled hospital test positivity of 0.9% (IQR 0.6–1.7%) in Week 14, and few hospitalisations attributed to COVID-19. The RSV burden among young children warrants continued clinical attention in paediatric inpatient settings as the season approaches its close.
One Health: Animal Disease Events in the European Region
The WOAH (World Organisation for Animal Health) database documents several significant animal disease events active in the European region during Week 15 that are relevant to the One Health interface. High pathogenicity avian influenza (HPAI) H5N1 continues to circulate in wild bird populations across multiple neighbouring countries, with active events recorded in Switzerland (ongoing since November 2025), Romania (ongoing since January 2026), Latvia (two concurrent events: H5N1 ongoing since September 2025, and a new H5N2 strain first detected in November 2025), and Czech Republic (ongoing since May 2025). African swine fever (ASF) remains active in Germany (first occurrence in the affected zone since January 2025) and Latvia (recurrence since December 2025), maintaining risk pressure on domestic and wild boar populations in the EU/EEA region. Rabies virus events are active in Tajikistan (recurrence since December 2025) and Moldova (recurrence since March 2026), countries sharing borders or close proximity with EU territory. Chlamydia abortus (ovine enzootic abortion) has been newly detected in a zone in Tajikistan since August 2025. These concurrent zoonotic hazards in the broader regional context reinforce the relevance of the One Health surveillance framework, particularly given the simultaneous detection of two novel avian influenza human cases (A(H7N7) in Taiwan and A(H9N2) imported into Italy) during the same reporting week.
Infectious Diseases: Bulgaria
Bloodborne and Contact/Sexual Transmission
Contact and Sexual Transmission
Gonorrhoea
Seven confirmed cases of gonorrhoea were registered in Week 15, representing a six-case increase from the single case recorded in the prior week—a 600% week-over-week increase that, while partially a reflection of low baseline numbers, nonetheless confirms the sustained upward trajectory characterising 2026. The cumulative year-to-date total of 74 cases compares with 21 cases in the same period of 2025, a 253% year-over-year excess. Neisseria gonorrhoeae infections carry dual public health importance: their direct impact through urethritis, cervicitis, pelvic inflammatory disease, and risk of infertility, and their broader epidemiological significance as sentinel markers of sexual risk behaviour and as the bacterial pathogen with the most rapidly evolving antimicrobial resistance profile globally. The 2026 Bulgarian gonorrhoea burden, if it continues at its current trajectory, will substantially exceed any previously recorded annual total in recent national surveillance history.
Urogenital Chlamydial Infection
Five confirmed cases of urogenital chlamydial infection were recorded in Week 15, down six from the eleven cases in Week 14 (−55% week-over-week). Despite this single-week reduction, the cumulative year-to-date total of 101 cases represents a 135% excess over the 43 cases registered in the same period of 2025. The pattern observed for chlamydia mirrors that of gonorrhoea, though at a larger absolute scale, consistent with the higher background prevalence of Chlamydia trachomatis infections and their predominantly asymptomatic clinical presentation. The year-over-year doubling of detected cases may reflect a genuine increase in transmission, expanded testing provision, or both; disaggregation of the 2026 excess by age, sex, and geographic distribution would be necessary to distinguish these mechanisms.
Respiratory and Droplet Transmission
Measles
The most significant new domestic signal in Week 15 is a substantial measles cluster concentrated in Vratsa district, which reported 24 cases in the current week—the highest single-district weekly count documented in 2026. An additional 5 cases were reported from Kyustendil district, with 3 from Lovech and 1 each from Gabrovo and Sofia-oblast, for a national total of 35 confirmed cases in Week 15. This represents a highly notable event given the historically low endemic measles transmission in Bulgaria following the introduction and sustained implementation of two-dose measles-mumps-rubella (MMR) immunisation; concentrated district-level outbreaks of this magnitude are indicative of a susceptibility gap, most likely in an age cohort, community, or geographic micro-area with suboptimal vaccination coverage. Measles virus (genus Morbillivirus) is transmitted via the respiratory route with an estimated R₀ of 12–18, and community immunity thresholds of at least 95% are required to interrupt transmission—a threshold that appears not to have been maintained in the affected areas. The Gabrovo district measles cluster that has been tracked in preceding weeks of 2026 appears to persist, while Vratsa represents a new geographic focus.
Scarlet Fever
Week 15 registered 56 cases of scarlet fever, representing a decrease of 24 cases from the 80 recorded in Week 14 (−30% week-over-week). This decline is consistent with the seasonal trajectory typically observed as school terms approach spring interruptions and winter respiratory season wanes. Geographically, Sofia-grad (18 cases) and Varna (9 cases) remained the principal foci, alongside Blagoevgrad (8), Plovdiv (4), and several other districts with sporadic cases. The year-to-date cumulative total of 1,123 cases remains 24.6% below the 1,489 cases registered in the same period of 2025, indicating that 2026 has seen a comparatively lighter scarlet fever season overall, notwithstanding the preceding weeks of elevated activity.
Varicella
Varicella activity continued its week-over-week decline in Week 15, with 601 cases registered compared with 661 in Week 14 (−60 cases; −9% week-over-week). Sofia-grad accounted for the largest district contribution (160 cases), followed by Varna (64), Blagoevgrad (58), Plovdiv (34), and Rusé (34). The year-to-date cumulative total of 9,122 cases remains marginally below the 9,445 cases recorded in the same period of 2025 (−323 cases; −3%), suggesting the 2026 varicella season is tracking close to the prior year but without exceeding it. The gradual weekly decline is consistent with the expected end-of-season pattern, though the absolute weekly case counts remain substantial and reflect the continued absence of universal childhood varicella vaccination in Bulgaria.
Fecal-Oral Transmission
Campylobacteriosis
Six confirmed cases of campylobacteriosis were registered in Week 15, a decline of three cases from the prior week. The cumulative year-to-date total of 149 cases compares with 57 cases in the same period of 2025—a 161% year-over-year excess. This represents the continuation of a striking, multi-week excess that has been documented consistently throughout 2026 and that has not yet been the subject of a formal epidemiological investigation communicated through NCIPD reporting. Campylobacteriosis is predominantly transmitted via consumption of undercooked poultry or contaminated water; its zoonotic reservoir in broiler chickens makes it particularly sensitive to changes in poultry production, slaughter hygiene, or food chain practices. The persistence of this excess across 15 consecutive weeks argues against a surveillance artefact and warrants coordinated One Health investigation.
Vector-Borne Transmission
Lyme Borreliosis
Four confirmed cases of Lyme borreliosis were registered in Week 15, up one from the prior week. The year-to-date total of 47 cases is marginally below the 54 cases registered in the same period of 2025 (−13%), indicating that the 2026 Lyme borreliosis season is not exceeding the prior year’s baseline at this stage. The early April period corresponds to the primary spring tick activity season in Bulgaria, and continued weekly monitoring is warranted. The geographic distribution this week included cases from Vracha, Gabrovo, and Shumen districts, consistent with the known enzootic distribution of Ixodes ricinus in forested and transitional habitat areas.