Bivalent COVID-19 mRNA booster vaccination (BA.1 or BA.4/BA.5) increases neutralization of matched Omicron variants.

We report SARS-CoV-2 neutralizing antibody titers in sera of triple-vaccinated individuals who received a booster dose of an original monovalent or a bivalent BA.1- or BA.4/BA.5-adapted vaccine or had a breakthrough infection with Omicron variants BA.1, BA.2 or BA.4/BA.5. A bivalent BA.4/BA.5 booster or Omicron-breakthrough infection induced increased Omicron-neutralization titers compared with the monovalent booster. The XBB.1.5 variant effectively evaded neutralizing-antibody responses elicited by current vaccines and/or infection with previous variants.

Febrile seizures in an urban Tanzanian population: lessons learned from a community-based random cluster survey.

OBJECTIVE: To analyse the cumulative incidence of febrile seizures, to evaluate the accuracy of our screening questionnaire and to describe clinical characteristics of children with febrile seizure in an urban population in Tanzania. METHODS: A large random cluster sampled population was screened for a febrile seizure history as part of a larger epilepsy study using a standardised questionnaire in a two-stage door-to-door survey in Tanzania. A subset of screen positive participants was further examined for confirmation of diagnosis and evaluation of clinical characteristics. RESULTS: Overall, 49 697 people were screened for a febrile seizure history of whom 184 (0.4%) screened positive. Women more commonly screened positive than men (112 [0.4%] vs. 72 [0.3%]). There was no marked difference between age groups or education. The positive predictive value of the screening tool was 37% (95% CI 24-51%) but its accuracy varied with the age of interviewed individuals. Cumulative incidence rates were estimated between 1.1% and 2.0% after adjusting for the inaccuracy of the screening tool. Most febrile seizures occurred before the age of two (65%) and most children had more than one episode (80%). A large proportion of children had complex febrile seizure (65%), often caused by malaria or respiratory infections. CONCLUSIONS: The community-based cumulative incidence of a febrile seizure history in an urban Tanzanian population was similar to rates reported from other rural populations after adjusting for the inaccuracy of our screening tool. Based on the integrated nature of the febrile seizure questionnaire, screening positivity rates may have been too low. This has implications for the design of future studies. The majority of cases had complex febrile seizures often associated with malaria. This has implications for clinical case management.

Prevalence of restless legs syndrome in an urban population of eastern Africa (Tanzania).

OBJECTIVES: Restless legs syndrome (RLS) is one of the most common neurological disorders in Caucasian populations with prevalence rates between 5% and 15%. A recent study conducted in rural northern Tanzania documented a prevalence of only 0.013%. This result requires further investigation of the epidemiology of RLS in Africa, as prevalence rates seem to vary among different ethnicities. PATIENTS/METHODS: We conducted a community-based door-to-door study in an urban environment in eastern Africa (Kinondoni district, Dar es Salaam, Tanzania), where 35.008 people aged 14 years and above were screened for RLS according to the essential diagnostic criteria. Sampling was performed by the method of cluster sampling with probability-proportional-to-size. RESULTS: One hundred and sixty-four people screened positively for RLS (0.47%). Ninety-two of those were subject to detailed history taking and physical examination. Four people could finally be diagnosed with RLS, yielding a RLS prevalence rate of 0.037% (95% CI 0.015%; 0.059%) among the people in Kinondoni. CONCLUSION: These results support previous findings that RLS has a very low prevalence in Tanzania despite the fact that only part of the questionnaire-positive RLS people could be interviewed face-to-face, and show that this is independent of whether assessed in a rural or an urban population. According to our results it seems that indigenous Tanzanian people (which are considered representative for the population of Eastern Africa) are less prone to RLS compared to Caucasian populations. Whether the reasons for this discrepancy in prevalence are primarily genetic, environmental or have a cultural/social component remains to be determined. In addition, the study points to a limited application of the essential diagnostic criteria in settings of non-Caucasian populations. Irrespective of ethnic origin, we support the necessity of detailed history and physical examination as performed in the second part of our study to exclude RLS mimics and verify the diagnosis of RLS.