SARS-CoV-2 prevalence and immunity: a hospital-based study from Malawi.

BACKGROUND: COVID-19 transmission and disease dynamics in sub-Saharan Africa are not well understood. Our study aims to provide insight into COVID-19 epidemiology in Malawi by estimating SARS-CoV-2 prevalence and immunity after SARS-CoV-2 infection in a hospital-based setting. METHODS: We conducted a hospital-based, convenience sampling, cross-sectional survey for SARS-CoV-2 in Lilongwe, Malawi. Participants answered a questionnaire and were tested for SARS-CoV-2 by enzyme-linked immunosorbent assay and real-time reverse-transcription polymerase chain reaction (RT-PCR). A surrogate virus neutralization test (sVNT) was performed in seropositive samples to estimate immunity. Poisson regression was used to assess SARS-CoV-2 point prevalence association with demographic and behavioral variables. FINDINGS: The study included 930 participants. We found a combined point prevalence of 10.1%. Separately analyzed, RT-PCR positivity was 2.0%, and seropositivity was 9.3%. Of tested seropositive samples, 90.1% were sVNT positive. We found a high rate (45.7%) of asymptomatic SARS-CoV-2 infection. SARS-CoV-2 point prevalence was significantly associated with being a healthcare worker. INTERPRETATION: Our study suggests that official data underestimate COVID-19 transmission. Using sVNTs to estimate immunity in Malawi is feasible and revealed considerable post-infection immunity in our cohort. Subclinical infection and transmission are probably a game-changer in surveillance, mitigation and vaccination strategies.

Adverse cardiorespiratory events following primary vaccination of very low birth weight infants.

OBJECTIVE: To examine the relationship between primary vaccination of preterm infants and prevalence ratios of associated factors for unwanted cardiorespiratory events, following the recommendation of the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices for immunization of preterm infants at 2 months of chronological age. METHODS: Two-year retrospective study of very low birth weight infants receiving their primary vaccination. Major cardiorespiratory events, such as apnea, bradycardia, SpO(2) desaturation, and minor adverse events, such as temperature instability, poor handling and local reactions, were recorded. Prevalence ratio with 95% confidence interval for associated factors between infants with and without cardiorespiratory events was calculated. RESULTS: Eighty neonates were studied (median [range] birth weight 970 g [428-1,490]), gestational age of 27.4 weeks (23.3-33). Adverse reactions occurred in 35 (44%): minor events in 19 (24%) patients, major events in 28 (35%). Infants with major events had significantly lower gestational age (p = 0.008) and a higher incidence of bronchopulmonary dysplasia (71% vs. 48%; p < 0.05). In very low birth weight infants with major events, O(2) desaturations before vaccination were 3.40 (1.41-8.23) times higher and treatment with methylxanthines for apnea and bradycardia syndrome was 8.05 (2.50-25.89) times higher compared to infants without major events. CONCLUSION: Major cardiorespiratory events occurred in over 1/3 of all very low birth weight infants after vaccination. Associated factors were low gestational age, bronchopulmonary dysplasia, methylxanthine treatment, and persisting O(2) desaturations before vaccination. Primary vaccination of very low birth weight infants should be performed under continuous monitoring of vital parameters.

Eventos cardiorrespiratórios adversos após vacinação primária de recém-nascidos de muito baixo peso / Adverse cardiorespiratory events following primary vaccination of very low birth weight infants

OBJETIVO: Examinar a relação entre vacinação primária de recém-nascidos pré-termo e razões de prevalência de fatores associados a eventos cardiorrespiratórios indesejados, seguindo recomendações do Comitê Consultivo de Práticas de Imunização do Centers for Disease Control and Prevention para imunização de recém-nascidos pré-termo aos 2 meses de idade cronológica. MÉTODOS: Estudo retrospectivo de 2 anos de recém-nascidos de muito baixo peso que receberam vacinação primária. Foram registrados eventos cardiorrespiratórios maiores, como apneia, bradicardia, dessaturação de SpO2, e eventos menores, como instabilidade de temperatura, comportamento inapropriado e reações locais. Foi calculada a razão de prevalência com intervalo de confiança de 95% para fatores associados entre recém-nascidos com e sem eventos cardiorrespiratórios. RESULTADOS: Foram estudados 80 recém-nascidos (mediana de peso ao nascer [:intervalo]: de 970 g [:428-1.490]:), idade gestacional de 27,4 semanas (23,3-33). Ocorreram reações adversas em 35 (44%): eventos menores em 19 (24%) pacientes, eventos maiores em 28 (35%). Recém-nascidos com eventos maiores tiveram idade gestacional significativamente menor (p = 0,008) e incidência mais alta de displasia broncopulmonar (71% versus 48%; p < 0,05). Em recém-nascidos de muito baixo peso com eventos maiores, o número de casos de dessaturação de O2 antes da vacinação foi 3,40 (1,41-8,23) vezes maior, e o tratamento com metilxantina para síndrome de apneia e bradicardia foi 8,05 (2,50-25,89) vezes maior em comparação com recém-nascidos sem eventos maiores. CONCLUSÃO: Eventos cardiorrespiratórios maiores ocorreram em mais de 1/3 de todos os recém-nascidos de muito baixo peso após a vacinação. Os fatores associados foram baixa idade gestacional, displasia broncopulmonar, tratamento com metilxantina e dessaturação de O2 persistente antes da vacinação. A vacinação primária de recém-nascidos de muito baixo peso deve ser realizada sob monitoramento contínuo de parâmetros vitais.

OBJECTIVE: To examine the relationship between primary vaccination of preterm infants and prevalence ratios of associated factors for unwanted cardiorespiratory events, following the recommendation of the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices for immunization of preterm infants at 2 months of chronological age. METHODS: Two-year retrospective study of very low birth weight infants receiving their primary vaccination. Major cardiorespiratory events, such as apnea, bradycardia, SpO2 desaturation, and minor adverse events, such as temperature instability, poor handling and local reactions, were recorded. Prevalence ratio with 95% confidence interval for associated factors between infants with and without cardiorespiratory events was calculated. RESULTS: Eighty neonates were studied (median [:range]: birth weight 970 g [:428-1,490]:), gestational age of 27.4 weeks (23.3-33). Adverse reactions occurred in 35 (44%): minor events in 19 (24%) patients, major events in 28 (35%). Infants with major events had significantly lower gestational age (p = 0.008) and a higher incidence of bronchopulmonary dysplasia (71% vs. 48%; p < 0.05). In very low birth weight infants with major events, O2 desaturations before vaccination were 3.40 (1.41-8.23) times higher and treatment with methylxanthines for apnea and bradycardia syndrome was 8.05 (2.50-25.89) times higher compared to infants without major events. CONCLUSION: Major cardiorespiratory events occurred in over 1/3 of all very low birth weight infants after vaccination. Associated factors were low gestational age, bronchopulmonary dysplasia, methylxanthine treatment, and persisting O2 desaturations before vaccination. Primary vaccination of very low birth weight infants should be performed under continuous monitoring of vital parameters.