Non-Communicable Disease and Healthcare System Developments
Chikungunya Vaccine Safety Update: Ixchiq and Aseptic Meningitis in Healthy Young Adults
The EMA Pharmacovigilance Risk Assessment Committee (PRAC) has concluded a targeted safety signal review of the live attenuated chikungunya vaccine Ixchiq (Valneva) and recommended an update to the product information to reflect an important revision to the known risk profile. The update is consequential: whereas aseptic meningitis and other neurological adverse events (encephalopathy, encephalitis) were already listed in the product information as reactions of unknown frequency, the population at recognised risk was previously characterised as individuals aged over 65 years or those with multiple chronic conditions. Following a reported case of aseptic meningitis in a healthy young adult post-vaccination, PRAC has now recommended explicit inclusion of healthy young adults in the labelled at-risk population for serious adverse events. This revision is not trivial from a clinical decision-making standpoint. Pre-travel vaccination counselling has heretofore been calibrated around a risk model that positioned young, healthy adults as the lower-risk stratum for post-vaccination neurological complications—a model this update materially alters. PRAC is simultaneously conducting a regular six-monthly periodic safety update report (PSUR) evaluation, expected to conclude in June 2026, which will provide a comprehensive reassessment of Ixchiq’s benefit–risk balance incorporating all newly available safety data. Until that assessment is complete, the current ECDC and PRAC position is that Ixchiq should only be administered when there is a genuine, significant risk of chikungunya infection, and that an individualized benefit–risk evaluation is mandatory across all age groups. Healthcare providers should be alert to neurological symptoms—confusion, somnolence, fever, headache, seizures, and neck stiffness—in any vaccinated individual and ensure immediate medical assessment if these arise.
CLOSURE-AF Trial: Left Atrial Appendage Closure Does Not Meet Non-Inferiority Threshold
A major randomised controlled trial published in the New England Journal of Medicine (March 2026) provides clinically important evidence regarding percutaneous left atrial appendage closure (LAAC) as a strategy for stroke prevention in patients with atrial fibrillation at high risk for both stroke and bleeding. The CLOSURE-AF trial, conducted across multiple German centres, randomised 912 patients (mean age 77.9 years; mean CHA₂DS₂-VASc score 5.2; mean HAS-BLED score 3.0) to LAAC or physician-directed best medical therapy, which included direct oral anticoagulants where eligible. Over a median follow-up of three years, the primary composite endpoint—stroke, systemic embolism, major bleeding, or cardiovascular or unexplained death—occurred in 16.8 events per 100 patient-years in the LAAC group versus 13.3 per 100 patient-years in the medical therapy group. The non-inferiority hypothesis was not confirmed (P = 0.44 for non-inferiority), with the confidence interval for the difference in restricted mean survival time crossing the pre-specified non-inferiority margin. Serious adverse events were numerically higher in the device arm (82.5% versus 77.4%). These findings, from a well-powered trial in a relevant high-risk population, do not support LAAC as a general alternative to pharmacological anticoagulation in elderly patients with atrial fibrillation who are eligible for direct oral anticoagulants, and should inform shared decision-making conversations in this population.
FAST Trial: Home-Based Tailored Intervention Reduces Falls After Stroke
A randomised trial published in The BMJ (March 2026) demonstrates a clinically and statistically significant reduction in falls among community-dwelling ambulatory stroke survivors through a multidisciplinary, home-based, tailored intervention. The FAST trial enrolled 370 participants from three Australian states; the experimental group received a six-month programme comprising habit-forming functional exercise, home hazard reduction, and goal-directed community mobility coaching delivered by physiotherapist–occupational therapist dyads. At twelve months, the experimental group demonstrated a 33% reduction in fall rates (incidence rate ratio 0.67, 95% CI 0.48–0.94; P = 0.02), with significant improvements in self-efficacy, mobility (fast walking speed +0.13 m/s), community participation, and balance. The public health relevance for stroke rehabilitation services lies in the structured dyadic delivery model and the explicit integration of habit formation and community reintegration, both of which address modifiable behavioural determinants of falls that are systematically underaddressed in standard post-rehabilitation follow-up.
Infectious Diseases: Global Perspective
Respiratory and Droplet Transmission
Avian Influenza A(H5N1)
On 15 March 2026, the Cambodian Ministry of Health reported a new human case of avian influenza A(H5N1) in an adult woman in her forties from Preah Netr Preah District, Banteay Meanchey province. The patient—isolated and receiving oseltamivir—had sustained contact with sick and dead poultry before onset of illness. No secondary cases have been detected among close contacts, who received oseltamivir prophylaxis. This is Cambodia’s second human A(H5N1) case of 2026; the first was reported in February. Clade 2.3.2.1e has been the dominant lineage in Cambodian poultry and has accounted for human cases previously. Cumulatively, Cambodia has reported 92 human A(H5N1) cases since 2003, including 52 deaths (case fatality rate 48%), which mirrors the global picture: 996 confirmed human cases and 477 deaths (CFR 48%) across 25 countries since 2003, with no evidence of sustained human-to-human transmission in any episode. ECDC maintains its overall risk assessment for the general EU/EEA population as low. The risk pathway remains anchored in direct, unprotected contact with infected or dead birds and contaminated environments; the importance of appropriate personal protective equipment in backyard and commercial poultry settings continues to be underscored by recent case clusters in Asia and the Americas.
Infectious Diseases: EU/EEA
Contact and Droplet Transmission
Invasive Meningococcal Disease — England, 2026
The most urgent communicable disease signal in the EU/EEA this week is an outbreak of invasive meningococcal disease (IMD) in Kent, England. As of 19 March 2026, the UK Health Security Agency (UKHSA) had reported 29 cases (18 laboratory-confirmed), including two deaths. Cases range in age from 17 to 21 years, and a substantial proportion are students at the University of Kent. Of 18 laboratory-confirmed cases, 13 were identified as meningococcal serogroup B, sequence type (ST) 485, clonal complex ST-41/44—a characterised lineage against which the Bexsero MenB vaccine is expected to provide immunological coverage. Epidemiological investigation has identified a Canterbury nightclub (Club Chemistry) as a probable exposure site during 5–7 March, in addition to the University of Kent campus. As of 19 March, 2,360 vaccinations and over 9,000 doses of prophylactic antibiotics had been administered as part of the emergency public health response. International spread has been confirmed: French authorities have notified UKHSA of one confirmed case in France in an individual who had attended the University of Kent.
IMD is caused by Neisseria meningitidis, transmitted via respiratory droplets and direct contact with respiratory secretions, with an incubation period of typically two to ten days. Clinical presentation ranges from meningitis to fulminant septicaemia with characteristic non-blanching petechial or purpuric rash, and the condition can progress to death within 24 hours. The highest incidence occurs in infants, young children, and adolescents or young adults—the precise demographic affected in this outbreak. Post-COVID-19 surveillance data submitted to ECDC document an increasing trend in serogroup B notification rates since 2021 across the EU/EEA, with serogroup B accounting for 57% of 1,895 IMD cases reported in 2023. ECDC assesses the risk to the general EU/EEA population as very low; for exposed, unvaccinated individuals in the Kent area, risk is characterised as moderate, declining to very low if more than ten days have elapsed since last possible exposure.
Clinicians in Bulgaria and across the EU/EEA should include recent travel to England—particularly Canterbury or the broader Kent region—in their differential assessment for any suspected IMD case. Confirmed or suspected cases in returning travellers warrant immediate notification to national surveillance authorities, and isolates should undergo molecular characterisation by whole-genome sequencing. Enhanced genomic surveillance and reporting to pubMLST.org or the European Meningococcal Epidemiology in Real Time database (EMERT-II) will facilitate rapid identification of any further multinational spread.
Vector-Borne Transmission
Dengue — Travel-Associated Cases from the Maldives
Multiple EU/EEA countries have reported increasing numbers of travel-associated dengue cases linked to travellers returning from the Maldives, reflecting a sharp and sustained rise in local dengue transmission in that country since 2025. In January 2026, the Maldives reported 631 confirmed cases—a more than eightfold increase compared to January 2025 (72 cases) and a 4.6-fold increase compared to January 2024 (138 cases). In 2026 to date, at least four EU/EEA countries have collectively reported a minimum of 46 imported dengue cases attributable to Maldives travel. Dengue fever, caused by any of four antigenically distinct serotypes (DENV-1 through DENV-4) of flavivirus, is transmitted by Aedes mosquitoes and clinically characterised by abrupt-onset high fever, severe headache, retro-orbital pain, myalgia, arthralgia, and rash; severe dengue, including dengue haemorrhagic fever and dengue shock syndrome, carries substantial case fatality risk particularly in secondary infections. ECDC assesses the current risk of onward transmission within mainland Europe as low given the unfavourable seasonal conditions for Aedes mosquito activity, but the risk for EU/EEA travellers visiting the Maldives is characterised as moderate. Travel medicine providers and clinicians should alert travellers to this risk and consider dengue in the differential of febrile illness with compatible syndrome in returning travellers from the region.
Respiratory Transmission
Respiratory Virus Activity: Seasonal Recession
Respiratory virus activity across the EU/EEA continues its expected late-winter decline in Week 12. Primary care consultation rates for acute respiratory illness (ARI) and influenza-like illness (ILI) have largely returned to baseline: of 13 reporting countries providing ARI consultation rates, six were at baseline; of 15 reporting ILI rates, 12 were at baseline with one at medium intensity. Influenza test positivity in primary care settings (pooled) stands at 6.2% (median; IQR 4.3–13%), down from the seasonal peak levels observed earlier in 2026. In hospitalised severe acute respiratory illness (SARI) settings, influenza positivity has similarly declined to a pooled 4.8% (IQR 3.7–6.4%). Influenza A subtypes A(H1N1)pdm09 and A(H3) are now co-dominant: season-to-date, A(H3) accounts for 59% of typed influenza specimens, with A(H1N1)pdm09 constituting 40%. Within the A(H3) subclade, 2a.3a.1(K) predominates at 89%.
Respiratory syncytial virus (RSV) activity and hospital admissions remain elevated relative to the seasonal baseline, with children under five years disproportionately represented among SARI admissions. RSV test positivity in primary care stands at 11% (IQR 7.3–18%), and in hospital settings at 15% (IQR 9.2–22%). SARS-CoV-2 circulation remains low across all age groups and settings: primary care positivity 1.7% (IQR 1.1–2.6%), SARI positivity 1.1% (IQR 0.3–0.8%). The dominant circulating SARS-CoV-2 variant remains NB.1.8.1, classified as a Variant Under Monitoring (VUM), accounting for approximately 92% of detections in Weeks 9–10. EuroMOMO all-cause mortality is reported at expected levels across all age groups.
Vaccine Safety
Chikungunya Vaccine — Ixchiq Safety Signal
Following the PRAC recommendation described in the non-communicable disease section above, the ECDC CDTR includes this update as a formal surveillance topic. The updated product information for Ixchiq represents a meaningful change to the vaccine’s safety labelling and should inform travel medicine practice across the EU/EEA. ECDC currently has no specific ongoing operational response to this event; monitoring continues through standard pharmacovigilance channels.
Infectious Diseases: Bulgaria (Week 12, 16–22 March 2026)
Bloodborne and Fecal-Oral Transmission
Campylobacteriosis
Eighteen confirmed cases of campylobacteriosis were registered in Week 12—a seven-case increase from the 11 cases of Week 11 (+64% week-over-week), representing the sharpest single-week rise observed in recent weeks. The cumulative year-to-date total of 126 cases stands at 180% above the 45 cases recorded in the same period of 2025 (an excess of 81 cases). Campylobacteriosis, caused by thermophilic Campylobacter species (predominantly C. jejuni and C. coli), is a zoonotic foodborne infection with a primary reservoir in domestic poultry; human exposure typically occurs via consumption of undercooked poultry, contaminated water, or raw milk. Clinical features include acute watery or bloody diarrhoea, abdominal cramping, and fever, usually self-limiting within five to seven days, though bacteraemia and complications such as reactive arthritis and Guillain-Barré syndrome can occur in vulnerable populations. The week 12 geographic distribution shows the two largest clusters in Sofia-grad (12 cases) and Ruse (4 cases), with single cases in Varna and Sofia-oblast, suggesting some degree of geographic concentration rather than fully diffuse national spread. The 180% year-over-year cumulative excess across twelve weeks is epidemiologically anomalous and warrants coordinated food safety investigation.
Respiratory and Droplet Transmission
Measles — Localised Cluster in Gabrovo
Eleven cases of measles were registered in Week 12, all concentrated in Gabrovo district. This is a clinically and epidemiologically significant finding: measles had not been reported in the NCIPD national weekly analyses for the preceding weeks of 2026, and the sudden appearance of a single-district cluster of eleven cases represents a potential localised outbreak requiring urgent investigation. Measles, caused by a paramyxovirus with an R₀ of 12–18, spreads via respiratory droplets and is one of the most transmissible human pathogens known; in populations with vaccination coverage below the 95% threshold required for herd immunity, self-sustaining chains of transmission can be established rapidly. Gabrovo district should be the immediate focus of investigation to determine the likely source, vaccination status of affected individuals, and the existence of any susceptible groups—including children with incomplete or absent MMR vaccination. In the context of the ongoing global and EU/EEA measles intensification documented in prior weeks (including the US outbreak of 1,281 cases and the active multi-country EU/EEA transmission), this Gabrovo cluster carries heightened public health urgency. The week 12 regional breakdown document provides district-level data one week behind the national analysis, which is the expected structural lag in this surveillance system; confirmation of the cluster and its epidemiological characterisation should follow from the national report.
Varicella
Varicella declined substantially in Week 12, with 519 cases registered—a 169-case decrease from the 688 recorded in Week 11 (−25% week-over-week). This brings the year-to-date total to 7,076 cases, which remains 7% below the 7,611 cases registered through Week 12 of 2025. The geographic distribution remains nationwide; Sofia-grad accounts for 139 cases (27%), followed by Blagoevgrad (51), Varna (46), and V. Tarnovo (29). The week-over-week decline is a welcome signal following the sharp rebound of Week 11, though given the high transmission potential of varicella in unvaccinated school-age populations, the risk of further periodic surges through the spring semester remains. Bulgaria’s national immunisation schedule does not include universal varicella vaccination.
Scarlet Fever
Ninety cases of scarlet fever were recorded in Week 12, a six-case increase from Week 11 (+7% week-over-week), which does not individually meet the 20% reporting threshold but contributes to a sustained elevated plateau of scarlet fever activity this season. The year-to-date total of 888 cases is 26% below the 1,202 cases registered in the same period of 2025, indicating that despite weekly counts remaining at substantive levels, this season’s overall scarlet fever burden is lower than last year’s. The geographic distribution is broad: Varna leads with 16 cases, followed by Sofia-grad (19), Plovdiv (10), Ruse (10), Silistra (10), and multiple other districts with smaller contributions. Scarlet fever, caused by Streptococcus pyogenes (group A streptococcus) secreting erythrogenic toxins, is a childhood infection of respiratory route transmission; the current activity level is consistent with expected late-winter seasonal patterns and does not suggest an unusual epidemiological event.
Fecal-Oral Transmission
Gastroenteritis and Enterocolitis
The 114 cases of gastroenteritis and enterocolitis registered in Week 12 represent a substantial 26-case decline from Week 11 (−19% week-over-week), consistent with a natural seasonal recession. The year-to-date total of 1,602 cases is virtually identical to the 1,607 cases in the corresponding period of 2025 (−0.3%), indicating stable endemic-level activity without a significant year-over-year departure. Eighteen rotavirus gastroenteritis cases were confirmed in Week 12, a one-case increase from Week 11 (+6%), with a year-to-date total of 170 cases—29% below the 239 cases in the same period of 2025. This relative reduction in confirmed rotavirus cases is consistent with the gradual expansion of rotavirus vaccination programmes in younger paediatric cohorts, though universal infant vaccination is not yet fully implemented at national level in Bulgaria.
Contact and Sexual Transmission
Gonorrhea
Ten confirmed cases of gonorrhea were registered in Week 12—a three-case increase from Week 11 (+43% week-over-week). The year-to-date cumulative total of 58 cases represents a 263% excess above the 16 cases documented in the same period of 2025 (an absolute excess of 42 cases), constituting the largest proportional year-over-year increase among all STIs under national surveillance in 2026. Neisseria gonorrhoeae is of particular concern given global trends in antimicrobial resistance, including documented cephalosporin-resistant and multidrug-resistant strains in the EU/EEA. The Bulgarian national surveillance system does not routinely include antimicrobial susceptibility testing data alongside case notifications, representing a gap in the information needed to characterise treatment implications and resistance patterns.
Urogenital Chlamydial Infection
Fourteen confirmed cases of urogenital chlamydial infection were recorded in Week 12—a seven-case increase from Week 11 (+100% week-over-week). This is a notably sharp single-week increase and the largest single-week case count registered for this condition in 2026 to date. The year-to-date total of 82 cases exceeds the 35 cases recorded in the same period of 2025 by 134% (an excess of 47 cases). The public health significance of this trend is amplified by the fact that chlamydial infection is predominantly asymptomatic—particularly in women—meaning that registered cases likely represent a fraction of true infections, and the observed increase may reflect both genuine transmission increases and heightened diagnostic vigilance.
Syphilis
Eight confirmed cases of syphilis were recorded in Week 12, a two-case increase from Week 11 (+33% week-over-week). The year-to-date total of 79 cases is 16% below the 94 cases registered in the same period of 2025, maintaining the pattern observed throughout 2026 in which syphilis—uniquely among monitored STIs—is not demonstrating a year-over-year increase. The year-to-date count of six cases of congenital and infantile syphilis reflects continued vertical transmission burden and underscores the necessity of universal antenatal screening and treatment protocols.
Meningococcal Disease
Three cases of invasive meningococcal disease (IMD) were registered in Bulgaria in Week 12—one possible and two confirmed—a three-case increase from zero in Week 11. This is the first week in 2026 that cases have been registered, and this total constitutes the entire year-to-date count of three cases, compared to seven cases in the same period of 2025. The three cases in Week 12 are geographically distributed: one in Sofia-grad, one in Stara Zagora (visible in the regional breakdown). While three cases in a single week can represent normal stochastic variation in a disease of low baseline incidence, this observation acquires additional significance in the context of the ongoing serogroup B outbreak in England. Clinical assessment for travel history to the Kent region is warranted for all IMD presentations, and all Bulgarian isolates should undergo serogroup and sequence typing. Four cases of viral meningitis and meningoencephalitis were also registered in Week 12, a four-case increase from zero the prior week, with two probable and two confirmed; the year-to-date total of 13 cases remains below the 22 cases in the same period of 2025.
Miscellaneous Notable Signals
COVID-19
Eleven confirmed COVID-19 cases were registered in Week 12—a four-case increase from Week 11 (+57% week-over-week). The year-to-date total of 295 cases is 21% above the 244 cases in the same period of 2025. While absolute case counts remain low and reflect the current era of reduced systematic testing rather than true disease burden, the week-over-week increase and the year-over-year excess are directionally noted. SARS-CoV-2 variant NB.1.8.1 (VUM) accounts for approximately 92% of sequenced detections in the EU/EEA as of Weeks 9–10, 2026.
HIV
Seven confirmed HIV cases were registered in Week 12—a three-case increase from Week 11 (+75% week-over-week). The year-to-date total of 54 cases is 23% below the 70 cases registered in the same period of 2025, continuing the modest year-over-year decline trend observed in earlier weeks of 2026.
Recommendations
- Clinicians across the EU/EEA should include recent travel to England—particularly to Canterbury or the broader Kent area—in the differential assessment of any suspected invasive meningococcal disease presentation; confirmed cases in returning travellers should be immediately notified to national authorities, and isolates referred for molecular typing. Close contacts of confirmed cases should receive prophylactic antibiotics and be monitored for symptoms for at least ten days from last possible exposure.
- The detection of eleven measles cases concentrated in Gabrovo district in Week 12 constitutes a probable localised outbreak and requires urgent public health investigation including rapid identification of the source, vaccination status of cases and exposed contacts, and deployment of reactive vaccination in any identified susceptible populations.
- The sustained 88% year-over-year excess in acute viral hepatitis ABCDEN through Week 12—confirmed across twelve consecutive weeks—demands expedited serotype-specific investigation; structural surveillance improvement through disaggregation of the ABCDEN aggregate into individual hepatitis serotypes should be treated as a public health priority.
- The 64% week-over-week rise in campylobacteriosis and the 180% year-to-date excess over 2025 in Bulgaria warrant coordinated food safety investigation, with source-attribution analysis focusing on poultry supply chains, water quality, and any changes in laboratory ascertainment.
- Healthcare providers and travel medicine services in Bulgaria and across the EU/EEA should counsel travellers to the Maldives about the currently elevated dengue risk and recommend both personal protective measures (insect repellent, appropriate clothing, accommodation with mosquito netting) and clinical vigilance for dengue in returning febrile travellers.
- Pre-travel vaccination counselling for chikungunya with Ixchiq should be updated to incorporate the PRAC-recommended labelling revision; the possibility of serious neurological adverse events including aseptic meningitis is no longer confined to older or immunocompromised individuals, and benefit–risk evaluation must be conducted individually regardless of age or health status.
- The 263% year-over-year excess in gonorrhea and the 134% excess in chlamydial infection through Week 12 reinforce the need for expanded STI screening, enhanced sexual health outreach, and systematic antimicrobial susceptibility surveillance for Neisseria gonorrhoeae within Bulgarian reference laboratory capacity.