The 2000 Hajj (March 15–18) was followed by an outbreak of Neisseria meningitidis W135 2a: P1.2,5 in Europe. From March 18 to July 31, 2000, some 90 cases of meningococcal infection were reported from nine countries, mostly the United Kingdom (UK) and France; 14 cases were fatal. Although most early cases were in pilgrims, the outbreak spread to their contacts and then to those with no known pilgrim contact. In France and the UK, the outbreak case-fatality rate was compared with the rate reported from national surveillance. The risk of dying during this outbreak was higher in France and the UK, although the difference was not statistically significant. Prophylaxis for all pilgrims and their household contacts was offered in France; in the UK and other European countries, prophylaxis was recommended only for close contacts. No difference in transmission rates following intervention was detected between France and the UK.

Invasive group A streptococcal (GAS) infections cause significant morbidity and mortality. A national survey was initiated to assess the burden of invasive GAS infections in France, describe their clinical characteristics, and assess the molecular characteristics of GAS strains responsible for these infections. The survey was conducted in 194 hospitals, accounting for 51% of acute care hospital admissions in France. Clinical data, predisposing factors, and demographic data were obtained, and all GAS isolates were emm sequence typed. We identified 664 cases of invasive GAS infections, with an annual incidence of 3.1 per 100,000 population. The case-fatality ratio was 14% and rose to 43% in the case of streptococcal toxic shock syndrome. Bacteremia without identified focus (22%) and skin/soft tissue infections (30%) were the most frequent clinical presentations. Necrotizing fasciitis was frequent in adults (18%) and uncommon in children (3%). The 3 predominant emm types were emm1, emm89, and emm28, accounting for 33%, 16%, and 10% of GAS isolates, respectively. The emm1 type was associated with fatal outcomes and was more frequent in children than in adults. Six clusters of cases were identified, with each cluster involving 2 invasive cases due to GAS strains which shared identical GAS emm sequence types. Four clusters of cases involved eight postpartum infections, one family cluster involved a mother and child, and one cluster involved two patients in a nursing home. Invasive GAS infection is one of the most severe bacterial diseases in France, particularly in persons aged >50 years or when associated with toxic shock syndrome.

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Between January 2003 and June 2005, an outbreak of meningococcal disease occured in the department of Seine-Maritime in northern France. Eighty six cases were notified, giving an average annual incidence of 2.7 cases per 100 000 inhabitants, compared with 1.6 in France. An especially affected area was defined as the city of Dieppe and its surrounding area (26 cases, giving an annual incidence of 12 cases per 100 000). This outbreak was due to N. meningitidis phenotype B:14:P1.7,16 belonging to the clonal complex ST-32/ET-5. Over the 31 B14:P1.7,16 cases confirmed by phenotyping methods at the national reference centre for meningococci (CNR, Centre National de Référence des méningocoques) the case-fatality rate (19%) and the proportion of purpura fulminans (42%) were especially high. Teenagers aged between 15 and 19 years and children aged 1 to 9 years were the most affected. In 2003, health authorities put in place enhanced epidemiological surveillance and informed practitioners and population about the disease. In 2004, the national vaccination advisory board studied the opportunity of using a non licensed outer membrane vesicle vaccine developed in Norway which may be effective against the B14:P1.7,16 strain. The Ministry of health decided in 2006 to offer vaccination with this vaccine to people aged 1 to 19 years in Seine- Maritime.

In January 2020, SARS-CoV-2 virus was identified as a cause of an outbreak in China. The disease quickly spread worldwide, and the World Health Organization (WHO) declared the pandemic in March 2020.From the first notifications of spread of the disease, the WHO’s Emergency Programme implemented a global COVID-19 surveillance system in coordination with all WHO regional offices. The system aimed to monitor the spread of the epidemic over countries and across population groups, severity of the disease and risk factors, and the impact of control measures. COVID-19 surveillance data reported to WHO is a combination of case-based data and weekly aggregated data, focusing on a minimum global dataset for cases and deaths including disaggregation by age, sex, occupation as a Health Care Worker, as well as number of cases tested, and number of cases newly admitted for hospitalization. These disaggregations aim to monitor inequities in COVID-19 distribution and risk factors among population groups.SARS-CoV-2 epidemic waves continue to sweep the world; as of March 2022, over 445 million cases and 6 million deaths have been reported worldwide. Of these, over 327 million cases (74%) have been reported in the WHO surveillance database, of which 255 million cases (57%) are disaggregated by age and sex. A public dashboard has been made available to visualize trends, age distributions, sex ratios, along with testing and hospitalization rates. It includes a feature to download the underlying dataset.This paper will describe the data flows, database, and frontend public dashboard, as well as the challenges experienced in data acquisition, curation and compilation and the lessons learnt in overcoming these. Two years after the pandemic was declared, COVID-19 continues to spread and is still considered a Public Health Emergency of International Concern (PHEIC). While WHO regional and country offices have demonstrated tremendous adaptability and commitment to process COVID-19 surveillance data, lessons learnt from this major event will serve to enhance capacity and preparedness at every level, as well as institutional empowerment that may lead to greater sharing of public health evidence during a PHEIC, with a focus on equity.

National surveillance of invasive meningococcal disease (IMD) is based on mandatory reporting. The case definition for surveillance notification was changed in mid-2002 to include cases without microbiological confirmation. The IMD alert detection system was enhanced in 2003 with daily reporting and weekly analysis by district, serogroup, and age. Evaluation of the exhaustivity of the surveillance with capture-recapture analysis allowed correcting for underreporting. In 2003, 803 cases were reported. After correction for under-reporting, the estimated incidence was 1.78 / 100 000. After excluding 'new' cases reported with new definition criteria, the 2002-2003 increase was 4%. Incidence decreased with age, with the highest values in infants less than 1 year (20/100 000), children aged between 1 and 2 years (11/100 000) and in teenagers of 17 years old(7/100 000). The overall case fatality rate was 12%. Fifty nine per cent of cases were due to serogroup B, 32% to C, 5% to W135, and 4% to Y and non-groupable meningococci. Patients with purpura fulminans treated with intravenous antibiotics before admission to hospital were shown to have lower fatality rates than those not treated. In 2001-2003, 5 situations required particular attention: two clusters of serogroup B IMD had set off mass prophylaxis, one outbreak due to a specific B IMD clonal complex with high case fatality rate, and two districts crossed the alert threshold for serogroup C IMD, 2/100 000, and mass vaccination was recommended.

Summary Background On April 25, 2017, a cluster of unexplained illnesses and deaths associated with a funeral was reported in Sinoe County, Liberia. Molecular testing identified Neisseria meningitidis serogroup C (NmC) in specimens from patients. We describe the epidemiological investigation of this cluster and metagenomic characterisation of the outbreak strain. Methods We collected epidemiological data from the field investigation and medical records review. Confirmed, probable, and suspected cases were defined on the basis of molecular testing and signs or symptoms of meningococcal disease. Metagenomic sequences from patient specimens were compared with 141 meningococcal isolate genomes to determine strain lineage. Findings 28 meningococcal disease cases were identified, with dates of symptom onset from April 21 to April 30, 2017: 13 confirmed, three probable, and 12 suspected. 13 patients died. Six (21%) patients reported fever and 23 (82%) reported gastrointestinal symptoms. The attack rate for confirmed and probable cases among funeral attendees was 10%. Metagenomic sequences from six patient specimens were similar to a sequence type (ST) 10217 (clonal complex [CC] 10217) isolate genome from Niger, 2015. Multilocus sequencing identified five of seven alleles from one specimen that matched ST-9367, which is represented in the PubMLST database by one carriage isolate from Burkina Faso, in 2011, and belongs to CC10217. Interpretation This outbreak featured high attack and case fatality rates. Clinical presentation was broadly consistent with previous meningococcal disease outbreaks, but predominance of gastrointestinal symptoms was unusual compared with previous African meningitis epidemics. The outbreak strain was genetically similar to NmC CC10217, which caused meningococcal disease outbreaks in Niger and Nigeria. CC10217 had previously been identified only in the African meningitis belt.

Meningococcal disease surveillance in most countries is based upon a combination of statutory notification systems and laboratory reporting, both of which are recognised to underestimate the true burden of disease. The incidence of meningococcal disease varies throughout Europe, and although there are many reasons for this, it is important to quantify the degree of under-ascertainment in order to validate international comparisons. Here, we review the literature on the ascertainment of meningococcal disease in Europe and the available methods for estimating the degree of under-reporting. We found that the sensitivity of surveillance varies between countries and over time, with estimates ranging from 40% to 96%. We identified five methods suitable for conducting ascertainment studies, from simple comparative studies to more complicated capture-recapture and regression analyses. Studies of ascertainment may be used to identify weaknesses and biases in surveillance data, and facilitate the improvement of these systems. These findings are relevant to the surveillance of other infectious diseases, particularly those with lower mortality and a lower public profile than meningococcal disease, for which ascertainment may be worse.