Non-Communicable Disease and Healthcare System Developments
Clinical Research Highlights
Three publications in high-impact journals this week carry direct relevance for clinical and public health practice.
Telitacicept for IgA Nephropathy (NEJM, Phase 3 Interim Analysis)
A prespecified interim analysis of the TELIGAN phase 3 trial, published in the New England Journal of Medicine, provides the first randomised evidence of clinically meaningful efficacy for telitacicept in IgA nephropathy. Telitacicept is a recombinant fusion protein that simultaneously neutralises both B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL), two cytokines central to the pathogenic cascade driving aberrant IgA1 glycosylation and subsequent mesangial deposition. The trial enrolled 318 adults with biopsy-proven disease and persistent proteinuria (≥1.0 g/day) despite maximum supportive care, randomised 1:1 to subcutaneous once-weekly telitacicept 240 mg or placebo.
At the primary endpoint of 39 weeks, the percentage change in 24-hour urinary protein-to-creatinine ratio was −58.9% in the telitacicept group versus −8.8% with placebo, corresponding to a relative difference of −55.0% (95% CI: −61.3 to −47.6; p<0.001). Equally important from a long-term nephroprotective standpoint, the percentage change in estimated glomerular filtration rate was −1.0% with telitacicept compared with −7.7% with placebo—a difference suggesting meaningful attenuation of ongoing renal functional deterioration over the 39-week observation window. Adverse events were more frequent in the active treatment arm (89.3% vs 78.6%), though serious adverse events were markedly less common (2.5% vs 8.2%), with no unexpected safety findings identified. IgA nephropathy is the most common primary glomerulonephritis globally and a leading cause of end-stage renal disease among young adults; effective disease-modifying therapy targeting the upstream immunological pathway rather than proteinuria alone represents a substantive advance in the management of this condition.
Weight Loss and Atrial Fibrillation in Older Adults: The LOSE-AF Trial (JAMA)
The LOSE-AF randomised clinical trial, published in JAMA, provides an important qualification to the prevailing clinical guideline recommendation that all patients with obesity and atrial fibrillation (AF) should undergo weight loss intervention. The trial enrolled 118 adults aged 60 to 85 years (mean age 68; 33% female) with overweight (BMI ≥27) and persistent AF undergoing electrical cardioversion at two UK centres. Participants were randomised to an 8-month low-calorie dietary and behavioural support programme (n=59) or usual care (n=59).
The intervention achieved its proximal goal: mean weight at 8 months was 92.6 kg in the intervention group versus 99.4 kg in controls (estimated difference −6.9 kg; 95% CI: −9.2 to −4.5; p<0.001), corresponding to a 9.7% weight reduction versus 3.1%. However, this clinically significant weight loss conferred no benefit on the primary outcome of AF symptom severity as measured by the Atrial Fibrillation Severity Scale (baseline-adjusted mean scores: 7.9 vs 8.9; between-group difference −0.9; 95% CI: −3.3 to 1.4; p=0.43). No significant treatment effects were observed on physical performance, AF burden, cardiac imaging parameters, blood pressure, lipid profile, or the need for repeat cardioversion or ablation. No serious adverse events related to trial participation occurred in either group. The trial’s principal public health significance lies in its demonstration that prior evidence supporting weight loss for AF—predominantly derived from younger patient populations—does not straightforwardly extend to older adults, among whom weight reduction programmes may carry the additional risk of precipitating or accelerating frailty. These findings highlight the importance of age-stratified evidence in clinical guideline development and should prompt re-evaluation of the strength of weight loss recommendations in this demographic.
Procalcitonin-Guided Antibiotic Duration in Neonatal Late-Onset Sepsis: The ProABIS Trial (BMJ)
The ProABIS multicentre randomised open-label trial, conducted across 33 neonatology departments in France and published in the BMJ, addressed whether procalcitonin (PCT)-guided decision-making can safely shorten antibiotic treatment duration in neonatal late-onset sepsis (LOS)—a common and potentially life-threatening complication of preterm birth and prolonged neonatal care. The trial enrolled 504 newborns (gestation ≥24 weeks, postnatal age >4 days) with suspected or proven LOS requiring antibiotics beyond 48 hours, randomised to PCT-guided management (n=248) or standard local protocols (n=256). In the PCT-guided arm, PCT concentrations were measured at randomisation and every two days; a non-binding recommendation to discontinue antibiotics was issued when PCT reached ≤0.5 µg/L.
The median duration of antibiotic treatment was 8 days in the PCT-guided group versus 10 days in the usual-care group (absolute difference −2.0 days; IQR: −3.8 to −1.0; p<0.001). Critically, non-inferiority for 28-day mortality was demonstrated: 2.4% versus 3.9% (absolute difference −1.5%; 95% CI: −5.0 to 1.8). Infection recurrence rates were also comparable (2.8% vs 3.9%). From a stewardship perspective, a two-day reduction in antibiotic exposure per sepsis episode, applied across the many thousands of LOS cases managed annually in European neonatal intensive care units, represents a meaningful reduction in cumulative antimicrobial pressure, with corresponding benefits for reducing the selection of resistant organisms in a setting where antimicrobial resistance constitutes a particularly severe threat.
Infectious Diseases: Global Perspective
Respiratory and Droplet Transmission
Avian Influenza A(H5N6) — Fatal Human Case, China
On 8 May 2026, WHO reported a further laboratory-confirmed human case of avian influenza A(H5N6) infection, bringing the cumulative total since 2014 to 94 cases with 58 deaths—a case fatality ratio of 62.4%. The case was a woman in her fifties from Chongqing Municipality, China, who developed symptoms on 16 April following direct exposure to live poultry that she had purchased, slaughtered, and consumed. She was hospitalised on 23 April with severe pneumonia and died on 3 May. Environmental sampling of her cutting board returned positive for influenza A(H5); none of her close contacts developed symptoms or tested positive for influenza virus.
The A(H5N6) subtype has been responsible for sporadic human infections almost exclusively in China (93 of 94 cases), with one additional case reported from Laos. The exposure pattern is consistent with the established epidemiology: more than 90% of cases report exposure to domestic poultry. No sustained human-to-human transmission has been documented to date, and ECDC’s assessment of the risk to the general public in EU/EEA countries remains very low. However, the consistently high case fatality ratio underscores the severity of disease in individuals who do acquire zoonotic infection, reinforcing the importance of personal protective measures for those with occupational or market-related poultry exposure.
Swine Influenza A(H1N2) Variant — Sporadic Case, United States
A single human infection with influenza A(H1N2) variant virus of swine origin was reported in Nebraska, United States, in the week ending 4 April 2026—the first A(H1N2)v case in the US for the 2026 calendar year and the second of the 2025–2026 season. The case, a person under 18 years of age, developed a self-limited respiratory illness requiring no hospitalisation and has since recovered. Epidemiological investigation identified no direct or indirect contact with pigs; a close contact developed concurrent mild respiratory illness, but no further linked cases were identified. Globally, 34 cases of human A(H1N2)v infection have been reported since 2019, including four cases in EU/EEA countries (Austria, Denmark, France, Netherlands). The absence of pig contact in this case is epidemiologically noteworthy, though limited non-sustained human-to-human transmission of swine-origin variant influenza viruses has previously been documented and is considered possible on rare occasions. ECDC continues to monitor variant influenza through epidemic intelligence activities.
Contact Transmission
Mpox — Global Outbreak Update: Pakistan Reclassified, Neonatal Cluster
The global mpox situation in Week 20 is notable for two developments. First, ECDC formally reclassified Pakistan to the category of countries with community transmission of monkeypox virus (MPXV) clade I, effective 13 May 2026, following a cluster of 249 suspected mpox cases—including 29 laboratory-confirmed—and 8 deaths reported across nine districts of Sindh province between 14 March and 20 April 2026. The cases were predominantly neonates, reflecting an unusual transmission context distinct from the predominantly sexual-network-driven clade I epidemiology observed in other affected countries. Clade Ib was identified as the circulating lineage in this cluster, which represents a significant epidemiological development given prior evidence linking clade Ib to enhanced transmissibility in close-contact household settings.
Second, the broader global epidemiological trajectory of mpox clade I continues its gradual decline. In the six-week period ending 3 May 2026, the five highest-burden African countries for confirmed clade I cases were Madagascar (656 cases), DRC (154 cases), and three others each reporting fewer than 100 cases. A decreasing trend in African clade I transmission—initially observed in May 2025—has continued into March 2026, though week-to-week fluctuations persist. Mpox clade II continues at a low and stable level outside Africa, with cases reported overwhelmingly among men (97%) who have sex with men (89%), predominantly adults. Secondary household transmission of clade I has been documented in Germany, Belgium, Ireland, and several non-EU/EEA countries, with cluster sizes ranging from 1 to 6 secondary cases. ECDC maintains its assessment that the risk of clade Ib infection is moderate for men who have sex with men and low for the general population in the EU/EEA.
Zoonotic Transmission
Andes Hantavirus — MV Hondius Cruise Ship Outbreak: Epidemiological Resolution
The Andes hantavirus outbreak aboard the Dutch-flagged cruise ship MV Hondius, first reported in Week 19, reached operational resolution this week following the completion of passenger and crew repatriation from Tenerife, Spain. As of 13 May 2026, the total case count stands at 11 (8 confirmed, 2 probable, 1 inconclusive) with 3 deaths, yielding a case fatality ratio of 27% among confirmed and probable cases. No new cases or deaths have been reported since the Week 19 update. The ship departed Tenerife on 11 May and is en route to the Netherlands.
Preliminary genomic sequencing of isolates from confirmed cases revealed a high degree of genetic similarity consistent with derivation from a common source, supporting the hypothesis of an initial zoonotic spillover event—most likely during the ship’s stop in Argentina, where Andes virus is endemic in wild rodents—followed by limited human-to-human transmission onboard. Person-to-person transmission of Andes virus (Hantavirus Andes orthohantavirus) is biologically unusual among hantaviruses; most other hantaviruses are transmitted exclusively via rodent excreta, and the documented capacity for direct human-to-human spread is a characteristic unique to the Andes genotype. The natural reservoir of Andes virus is the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), which is absent from Europe, precluding any risk of rodent-to-human secondary transmission among repatriated passengers. ECDC assesses the risk to the general EU/EEA population as very low.
Infectious Diseases: European Union / European Economic Area
Contact and Sexual Transmission
Mpox in the EU/EEA — Clade I Autochthonous Transmission Continuing
Within the EU/EEA, the epidemiological pattern of mpox clade I established since October 2025 persists into Week 20 without major change. Multiple EU/EEA countries continue to report clade I cases among men who have sex with men, the majority without recent travel history to Africa, indicating sustained autochthonous sexual-network transmission. Confirmed limited secondary household transmission has been documented in Germany, Belgium, and Ireland. ECDC’s Threat Assessment Brief of October 2025 remains current, with a moderate risk assessment for men who have sex with men and a low risk assessment for the general population. Current guidance emphasises pre-exposure vaccination strategies prioritising gay, bisexual, and transgender people and men who have sex with men, accessible testing, active contact tracing and partner notification, and continued community engagement. The mpox clade II situation in the EU/EEA—predominantly sexually transmitted at low and stable levels among men who have sex with men—is unchanged from prior weeks.
Zoonotic and Vector-Borne Transmission
High Pathogenicity Avian Influenza H5N1 — Ongoing European Poultry and Wild Bird Detections
WOAH surveillance data updated through mid-May 2026 document continued HPAI H5N1 detections in European poultry and wild bird populations. The Netherlands has ongoing reports in both poultry (FUR_32, recurrence since October 2025) and wild birds; Poland continues to report multiple active African swine fever and HPAI foci, with a new H5N1 poultry detection in April 2026 (FUR_6); France reported a new poultry focus (FUR_1) with a start date of 25 April 2026; Hungary has reported five poultry foci since January 2026; and the United Kingdom maintains multiple concurrent wild bird detections involving both H5N1 and H5N5 subtypes. These ongoing European HPAI H5N1 detections, while primarily of veterinary and agricultural significance, maintain the background zoonotic transmission risk for individuals with occupational poultry exposure. Romania reported a new Bluetongue virus serotype 3 detection on 3 May 2026, adding to the continued spread of this arboviral sheep disease across southeastern Europe.
Foot-and-Mouth Disease SAT 1 — Greece
As noted in the Week 19 report, Greece continues to record FMD SAT 1 foci (FUR_7, recurrence since 15 March 2026), and Cyprus confirmed a new SAT 1 strain on 19 February 2026 (FUR_16). SAT 1 is not a serotype historically endemic to Europe; its circulation in the eastern Mediterranean warrants continued heightened surveillance given the potential for spread to livestock populations in neighbouring Balkan and southeastern European countries, including Bulgaria.
Infectious Diseases: Bulgaria
Respiratory and Droplet Transmission
Varicella
Varicella registered 576 cases in Week 20, a decline of 133 cases from Week 19’s 709 (−18.8% week-over-week). The year-to-date cumulative total of 12,226 cases is essentially level with the 12,209 cases recorded in the same 20-week period of 2025 (+0.1%), confirming that the 2026 season is tracking closely to the prior year’s trajectory overall. The regional distribution in the ZRZ breakdown shows continued broad geographic dispersal, with the largest district contributions from Sofia-grad (125 cases), Varna (65), Blagoevgrad (56), Plovdiv (29), Haskovo (59), and Sliven (33)—a pattern consistent with school-age transmission across all major urban centres. The modest week-over-week decline likely reflects the approach of the late-spring school closure period, which characteristically attenuates varicella transmission. The incidence trajectory through Weeks 21–22 will indicate whether this represents the definitive beginning of the seasonal downslope or a transient fluctuation.
Measles — Continued Geographic Expansion
Twenty-five measles cases were reported via the ZRZ regional breakdown for Week 20, compared with 33 cases in Week 19—a decrease of 8 cases (−24% week-over-week). However, this apparent quantitative improvement is epidemiologically offset by the observation of geographic expansion: while the Week 19 outbreak was concentrated in Vracha, Pleven, Lovech, and Kyustendil, Week 20 introduces active transmission in two new districts—Montana (2 cases) and Sofia-grad (1 case)—in addition to continued substantial activity in Vracha (9 cases) and Pleven (9 cases), with Kyustendil contributing 4 cases. The emergence of cases in Sofia-grad is of particular surveillance concern given the city’s population density, transit connectivity, and the potential for rapid amplification within susceptible sub-populations.
Measles, caused by Morbillivirus hominis and transmitted via respiratory droplet and airborne routes with a secondary attack rate approaching 90% in susceptible contacts, remains the most infectious agent in routine surveillance. The disease’s characteristic 10–12-day incubation period and the 2–4-day prodromal infectious period preceding rash onset facilitate efficient forward transmission in settings with incomplete vaccination coverage. The ongoing multi-district outbreak—now spanning five districts across multiple epidemiological weeks—constitutes an active vaccine-preventable disease event requiring coordinated emergency vaccination response and enhanced case ascertainment.
Scarlet Fever
Scarlet fever notifications declined to 37 cases in Week 20, a reduction of 20 cases from Week 19’s inferred 57 (−35% week-over-week). The year-to-date total of 1,374 cases is 30.2% below the 1,969 cases registered in the same period of 2025, confirming a substantially less active Streptococcus pyogenes season in 2026 compared with the prior year. The geographic distribution in the ZRZ breakdown shows Sofia-grad (7), Plovdiv (6), and Ruse (5) as the principal contributing districts. The week-over-week decline is consistent with seasonal spring attenuation of streptococcal respiratory disease as school terms approach their end. No signals of unusually severe disease or complications have been reported in the national surveillance data.
Fecal-Oral Transmission
Campylobacteriosis
Campylobacteriosis registered 13 confirmed cases in Week 20, unchanged from Week 19. The year-to-date total of 215 cases is 107% above the 104 cases registered through the same period of 2025—a sustained doubling of reported campylobacteriosis incidence that has persisted across all 20 weeks of the 2026 surveillance year. The stable week-over-week count is consistent with continued plateau-level activity. Campylobacter jejuni and coli, the principal enteric bacterial pathogens in this category, are transmitted primarily via contaminated poultry and unpasteurised dairy products, with seasonal peaks typically emerging in late spring through summer in temperate climates. The 107% year-over-year excess warrants source attribution investigation, particularly in relation to poultry supply chain hygiene standards.
Gastroenteritis and Enterocolitis
A total of 194 cases of gastroenteritis and enterocolitis were registered in Week 20, a modest increase of 9 from Week 19 (+4.9% week-over-week). The year-to-date cumulative total of 3,009 cases is 4.0% above the 2,893 cases registered in the same period of 2025. Of the Week 20 cases, 79 were classified as possible, 107 as probable, and only 8 as confirmed—a case classification distribution reflecting the non-specific clinical case definition applied to this category. The ZRZ breakdown shows Plovdiv (39), Varna (23), V. Tarnovo (8), Lovech (14), and multiple other districts contributing in single figures. The year-over-year excess is minor and below the 20% inclusion threshold; the indicator is noted here for context given the concurrent hepatitis ABCDEN surge and the approaching warm season, during which enteric disease activity typically intensifies.
Rotavirus Gastroenteritis
Twenty-one confirmed cases of rotavirus gastroenteritis were registered in Week 20, a 4-case increase from the 17 cases in Week 19 (+24% week-over-week). The year-to-date total of 323 cases is 10.8% below the 362 cases recorded in the same period of 2025. The modest week-over-week increase is consistent with the characteristic late-spring tail of the rotavirus season in Bulgaria, which typically peaks between February and April. The geographic distribution in the ZRZ shows cases in Stara Zagora (5), Burdgas (2), Varna (4), Kardzhali (1), Kyustendil (1), and Plovdiv (3), among others.
Vector-Borne Transmission
Marseille Fever — Seasonal Onset Confirmed
Four cases of Mediterranean spotted fever (Marseille fever) were registered in Week 20, a three-case increase from the single case recorded in Week 19 (+300% week-over-week). The year-to-date total of 7 cases is 50% below the 14 cases registered in the same period of 2025. The ZRZ breakdown attributes 2 cases to Burgas district. Marseille fever, caused by Rickettsia conorii and transmitted primarily by the brown dog tick (Rhipicephalus sanguineus), characteristically begins its seasonal emergence in Bulgaria from May onward as rising temperatures activate tick populations. The threefold week-over-week increase represents the definitive onset of the 2026 Marseille fever season; activity is expected to escalate progressively through June, July, and August. Clinicians in tick-endemic areas should maintain heightened suspicion for the classic triad of fever, eschar, and maculopapular rash, particularly in patients with recent tick exposure or outdoor activity history.
Q Fever
Two confirmed cases of Q fever were registered in Week 20, compared with zero in Week 19. The year-to-date total of 24 cases is 50% above the 16 cases registered in the same period of 2025, and both Week 20 cases were identified in Burgas district—the same district contributing the Marseille fever cluster above, suggesting active tick-borne and zoonotic disease pressure in this southeastern coastal region. Q fever, caused by Coxiella burnetii, is a zoonotic infection transmitted primarily via inhalation of aerosols from contaminated animal products (particularly birth materials from infected sheep and goats), with tick transmission playing a secondary role. The incubation period ranges from 2 to 4 weeks; clinical presentation ranges from self-limited febrile illness to pneumonia, hepatitis, and—in a minority of cases—chronic endocarditis, which carries significant morbidity.
Lyme Borreliosis
Four confirmed cases of Lyme borreliosis were registered in Week 20, a decrease of 2 from the 6 cases in Week 19 (−33% week-over-week). The year-to-date total of 64 cases is 14.7% below the 75 cases recorded in the same period of 2025. The week-over-week decline follows the doubling documented in Week 19 and likely reflects normal variability within the early tick season rather than a substantive downward trend; sustained surveillance through May and June will be the key indicator of the 2026 tick season’s overall intensity. Cases this week were distributed across Pernik (1), Sofia-oblast (1), and Targovishte (1), with one additional case elsewhere.
Contact and Sexual Transmission
Urogenital Chlamydial Infection — Acute Weekly Surge
Thirteen confirmed cases of urogenital chlamydial infection were registered in Week 20, an increase of 11 from the 2 cases registered in Week 19—a 550% week-over-week increase representing the most dramatic single-week proportional change observed in the sexually transmitted infection surveillance data for 2026. The year-to-date cumulative total of 130 cases is 165% above the 49 cases registered in the same period of 2025. While the low absolute weekly baseline in prior weeks means that the 550% figure reflects both genuine signal and the statistical amplification of small numbers, the concurrent year-to-date excess of 165% over 20 weeks is too consistent and sustained to be attributed to reporting artefact alone. Chlamydia trachomatis infection, typically asymptomatic in a substantial proportion of infected individuals—particularly women—is likely substantially under-ascertained in routine surveillance. The sustained year-over-year excess may reflect genuine increases in transmission incidence, improvements in testing access, or enhanced reporting completeness, but the week-over-week surge warrants monitoring over the subsequent two to three weeks to characterise its trajectory.
Gonorrhea
Three confirmed cases of gonorrhea were registered in Week 20, one fewer than Week 19 (−25% week-over-week). The year-to-date cumulative total of 92 cases represents a 229% excess over the 28 cases registered in the same period of 2025. This sustained year-over-year excess—documented consistently since Week 1 of 2026—remains the most pronounced sustained relative increase among all tracked infections in Bulgarian national surveillance for the current year. The absence of antimicrobial susceptibility data in routine Bulgarian gonorrhea surveillance notifications, in the context of global emergence and geographic spread of extensively drug-resistant Neisseria gonorrhoeae, continues to represent a structurally significant gap that limits the assessment of treatment failure risk and clinical management guidance.
Syphilis
Four confirmed syphilis cases were registered in Week 20, a 10-case decrease from the 14 cases in Week 19 (−71% week-over-week). The year-to-date total of 142 cases is 9.2% above the 130 cases in the same period of 2025. The sharp decline from Week 19’s surge likely reflects the resolution of a reporting consolidation artefact rather than a true rapid reduction in transmission. Congenital syphilis recorded 2 confirmed cases in Week 20, compared with zero in Week 19; the year-to-date total of 16 cases is 33% above the 12 cases registered in the same period of 2025, representing continued preventable vertical transmission burden.
Mpox — First Confirmed Case of 2026 in Bulgaria
One confirmed case of mpox was registered in Week 20, the first confirmed mpox case in Bulgaria in the 2026 surveillance year. The year-to-date total stands at 1 case, compared with 2 cases registered through the same period of 2025. The case is consistent with the ongoing global mpox clade I epidemiological context described above, in which sporadic cases continue to be detected across EU/EEA countries including among men who have sex with men without recent travel history. Full epidemiological characterisation of this case—including clade identification, contact history, and exposure classification—will be important for determining whether this represents a travel-associated importation or autochthonous transmission.
HIV
Four confirmed HIV cases were registered in Week 20, one fewer than in Week 19 (−20% week-over-week). The year-to-date total of 90 cases is 24.4% below the 119 cases registered in the same period of 2025. The year-over-year decline, while potentially indicating a genuine reduction in newly diagnosed infections, should be interpreted with caution given Bulgaria’s well-documented pattern of late HIV diagnosis and the possibility of pandemic-period and post-pandemic testing backlog effects confounding year-over-year comparisons.