<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Diana Erazo</style></author><author><style face="normal" font="default" size="100%">Maria F Vincenti-Gonzalez</style></author><author><style face="normal" font="default" size="100%">Joris Van Loenhout</style></author><author><style face="normal" font="default" size="100%">Pierre Hubin</style></author><author><style face="normal" font="default" size="100%">Mathil Vandromme</style></author><author><style face="normal" font="default" size="100%">Piet Maes</style></author><author><style face="normal" font="default" size="100%">Maxime Taquet</style></author><author><style face="normal" font="default" size="100%">Johan Van Weyenbergh</style></author><author><style face="normal" font="default" size="100%">Lucy Catteau</style></author><author><style face="normal" font="default" size="100%">Simon Dellicour</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Investigating COVID-19 Vaccine Impact on the Risk of Hospitalisation through the Analysis of National Surveillance Data Collected in Belgium.</style></title><secondary-title><style face="normal" font="default" size="100%">Viruses</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aged</style></keyword><keyword><style  face="normal" font="default" size="100%">Belgium</style></keyword><keyword><style  face="normal" font="default" size="100%">COVID-19</style></keyword><keyword><style  face="normal" font="default" size="100%">COVID-19 Vaccines</style></keyword><keyword><style  face="normal" font="default" size="100%">Hospitalization</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">SARS-CoV-2</style></keyword><keyword><style  face="normal" font="default" size="100%">Vaccination</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2022 Jun 16</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">14</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The national vaccination campaign against SARS-CoV-2 started in January 2021 in Belgium. In the present study, we aimed to use national hospitalisation surveillance data to investigate the recent evolution of vaccine impact on the risk of COVID-19 hospitalisation. We analysed aggregated data from 27,608 COVID-19 patients hospitalised between October 2021 and February 2022, stratified by age category and vaccination status. For each period, vaccination status, and age group, we estimated risk ratios (RR) corresponding to the ratio between the probability of being hospitalised following SARS-CoV-2 infection if belonging to the vaccinated population and the same probability if belonging to the unvaccinated population. In October 2021, a relatively high RR was estimated for vaccinated people &amp;gt; 75 years old, possibly reflecting waning immunity within this group, which was vaccinated early in 2021 and invited to receive the booster vaccination at that time. In January 2022, a RR increase was observed in all age categories coinciding with the dominance of the Omicron variant. Despite the absence of control for factors like comorbidities, previous infections, or time since the last administered vaccine, we showed that such real-time aggregated data make it possible to approximate trends in vaccine impact over time.&lt;/p&gt;
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