Meningitis and encephalitis in Poland in 2021.

Introduction: Meningitis meningitis and/or encephalitis regardless of etiology are subject to monitoring in Poland as part of routine epidemiological surveillance. In this paper, meningitis and/or encephalitis in 2021 caused by Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and tick-borne encephalitis virus are discussed in detail. In Poland, immunoprophylaxis in the form of mandatory or recommended vaccinations is used to prevent diseases caused by the aforementioned etiological agents. Aim of the study: The aim of this study was to assess the epidemiological incidence of meningoencephalitis and encephalitis in Poland, in 2021 including analysis of the impact of the COVID-19 pandemic. Material and methods: To analyse the epidemiological situation of neuroinfections in Poland, we used data sent to NIPH NIH - NRI by Voivodeship Sanitary and Epidemiological Stations and published in the annual bulletin: "Infectious diseases and poisonings in Poland in 2021" and "Protective vaccination in Poland in 2021" as well as individual epidemiological interviews recorded in the EpiBase system. Results: In 2021, a total of 973 cases of meningitis and/or encephalitis were registered in Poland. This is a 16.1% increase in the number of cases compared to 2020, but still a 57% decrease in the number of cases compared to 2019 when 2,249 cases were recorded. For infections of bacterial etiology, including cases of neuroborreliosis, the number of cases increased by 38.3% (from 376 to 520, incidence from 0.96 to 1.76 per 100,000). Compared to 2020 and 2019, the incidence of meningitis and/or encephalitis of N. meningitidis decreased by 10.7% (from 0.13 to 0.15) and 47.4% (from 0.25 to 0.13), respectively, and for H. influenzae by 75% (from 0.01 to 0.03) and 70% (from 0.01 to 0.03). For S. pneumoniae, we can speak of an increase in incidence against 2020 of 57.1% (121 vs 77 cases, incidence 0.32 vs 0.20) and a decrease against 2019. (121 vs 190, incidence 0.32 vs 0.47). Infections of viral etiology accounted for 47% of all registered cases. There was a slight decrease in their number, by 2% (from 462 to 453 cases). In addition, there was an increase in cases of tick-borne encephalitis, from 158 in 2020 to 210 in 2021 (an increase of 32.9%), and a decrease in cases from 265 in 2019 (a decrease of 20.8%). Summary and conclusions: 2021 showed an overall upward trend in the number of recorded cases of bacterial meningitis and/or encephalitis, and a slight decrease in the number of viral meningitis and/or encephalitis cases compared to 2020. Still, the observed number of meningitis and/or encephalitis cases in 2021, both bacterial and viral incidences, remains below the levels observed in the pre-pandemic COVID-19 period (2019). As a result of the SARS-CoV-2 outbreak, the introduction of measures to limit the transmission of the SARS-CoV-2 virus has been observed to reduce the spread of other droplet- and airborne pathogens, thus also pathogens such as S. pneumoniae, H.influenzae and N. menningitidis.

Meningitis and encephalitis in Poland in 2020.

INTRODUCTION: Meningitis and/or encephalitis are one of the main infectious diseases of the nervous system. These diseases are most commonly caused by bacterial and viral etiological factors. In this publication, meningitis and/or encephalitis caused by Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and those with a viral origin - in Poland, most often caused by tick-borne encephalitis virus - are presented in detail. In addition to epidemiological surveillance, immunoprophylaxis in the form of mandatory and recommended vaccinations is used in Poland to prevent these infections. AIM OF THE STUDY: The aim of this study was to to assess the epidemiological situation of meningitis and encephalitis in Poland, in 2020. MATERIAL AND METHODS: To analyse the epidemiological situation of neuroinfections in Poland were used data sent to NIPH NIH - NRI by Voivodeship Sanitary and Epidemiological Stations and published in the annual bulletins: "Infectious diseases and poisonings in Poland in 2020" and "Protective vaccination in Poland in 2020" and individual epidemiological interviews registered in the EpiBaza system. RESULTS: In 2020, a total of 831 cases of meningitis and/or encephalitis were registered in Poland. This is a decrease in incidence of up to 62.9% compared to 2019. For infections of bacterial etiology, including cases of neuroborreliosis (incidence of 2.40 per 100,000), the number of cases decreased by 60.4% (from 931 to 369). In the viral infection group, there was a 64.9% decrease (from 1,318 to 462 cases). Of all registered cases, 56% were infections with a viral etiology. Compared to 2019, the number of cases with an S. pneumoniae etiology decreased by 61.3% and for N. meningitidis by 41.1%. It is interesting to note that, in the case of H. influenzae, we can speak of a 20% increase in cases compared to the previous year. In addition, we can see a decrease in the incidence of tick-borne encephalitis - from 265 in 2019 to 158 in 2020 (a decrease of 40.4%). SUMMARY AND CONCLUSIONS: Overall, a downward trend in incidence was shown for both bacterial and viral meningitis and/or encephalitis. The SARS-CoV-2 pandemic and the introduction of restrictions on personto-person contact and various forms of activity, resulting in a reduction in pathogen transmission, were key to the significant reduction in the number of meningitis and/or encephalitis cases in 2020, but a reduction in the availability of medical facilities or the completeness of case reports due to the burden of anti-epidemic measures on the Sanitary Inspectorate cannot be excluded either. Only in the case of cases caused by H. influenzae was a slight increase observed compared to the previous year (12 versus 10 cases). Meningoencephalitis and/or encephalitis, due to its wide etiological range, poses a major challenge to the health care system, particularly in terms of correct clinical diagnosis.