The public defence will be held as a video conference over Zoom.
The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.
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Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.
Digital Trial Lecture – time and place
Adjudication committee
- First opponent: Professor Tomas Bergstrøm, Sahlgrenska Academy, University of Gothenburg
- Second opponent: Professor Jan Egil Afset, St. Olavs Hospital/NTNU
- Third member and chair of the evaluation committee: Senior researcher Gunnveig Grødeland, University of Oslo
Chair of the Defence
Professor Jan Terje Andersen, Faculty of Medicine, University of Oslo
Principal Supervisor
Associate professor Susanne G. Dudman, Faculty of Medicine, University of Oslo
Summary
Acute gastroenteritis in children under five years of age is frequently caused by rotavirus and severe cases are often hospitalised. In 2014, a monovalent rotavirus vaccine was implemented in the national immunization program in Norway. The main objective of this thesis is to investigate the diversity of circulating rotavirus strains in Norway before and after the vaccine introduction.
We used clinical specimens and data from a multicentre hospital study to characterize the rotavirus cases admitted to hospital due to acute gastroenteritis in 2014 and the following four years. We used validated methods at the Rotavirus Reference Laboratory at the Norwegian Institute of Public Health to detection and genotyping of the strains. We also studied the sensitivity of rectal swabs versus bulk stool for these analyses. The cases were also checked for the co-infection with adenovirus, astrovirus and norovirus.
Our results show that the number of rotavirus cases was quickly reduced after vaccine implementation in this age group. The percentage of positive rotavirus samples fell from 40% to 0.4% during the four years in the study period. The prevalence of co-infections with adenovirus, astrovirus or norovirus also diminished after the first year.
We observed that the genetic diversity of rotavirus did not change much during the study period. This indicate that the monovalent rotavirus vaccine efficiently prevented all circulating genotypes during this period.
We found that in as much as 21% of the positive samples, rotavirus vaccine strain could be found. This is important knowledge for laboratories conducting routine testing of rotavirus suspected cases who recently were vaccinated. In these cases, further characterization to verify vaccine strain by genotyping is needed to distinguish them from the wild-type rotavirus.
We found that the sensitivity of rectal swabs was almost equal to bulk stool for the two detection methods and for genotyping. Rectal swab is an easier sampling method that can be used for the diagnosis of rotavirus infection in the routine laboratory and in disease surveillance projects.
Additional information
Contact the research support staff.