Diversity of Rotavirus Strains Circulating in Botswana before and after introduction of the Monovalent Rotavirus Vaccine.

2019

6324-6328

2019 Oct 08

1873-2518

<p><strong>BACKGROUND: </strong>Globally, rotavirus is the leading cause of acute gastroenteritis (AGE) in children aged &lt;5 years. Botswana introduced the monovalent rotavirus vaccine (Rotarix) in July 2012. To study the impact of this vaccine on rotavirus genotypes circulating in Botswana, a comparison of the genotypes pre-vaccination (2011-2012) and post-vaccination (2013-2018) periods was conducted.</p>

<p><strong>SUBJECTS AND METHODS: </strong>Residual samples from 284 children &lt;5 years of age that tested positive for rotavirus by enzyme immunoassay were genotyped. One hundred and five samples were from the pre-vaccination period and 179 were from the post-vaccination period. Genotyping was performed using two multiplexed one-step reverse transcription polymerase chain reaction (RT-PCR) assays for the amplification and genotyping of rotavirus VP7 (G) and VP4 (P) genes.</p>

<p><strong>RESULTS: </strong>Prior to vaccine introduction, the predominant rotavirus circulating genotypes were G9P[8] (n = 63, 60%) and G1P[8] (n = 22, 21%). During the vaccine period, G2P[4] was the predominant genotype (n = 49, 28%), followed by G9P[8] (n = 40, 22%) and G1P[8] (n = 33, 18.5%). There was a significant decline in the prevalence of G9P[8] (p = 0.001) in the post-vaccination period. There was also a notable decline in G1P[8]. A spike in G2P[4] was observed in 2013, one year post-vaccine introduction. Rotavirus strain G3P[4] (n = 8) was only detected in the post-vaccine introduction period. In 2018 there was a marked increase in genotype G3P[8] (p = 0.0003).</p>

<p><strong>CONCLUSIONS: </strong>The distribution of circulating rotavirus genotypes in Botswana changed after vaccine implementation. Further studies are needed to examine whether these changes are related to vaccination or simply represent natural secular variation.</p>

10.1016/j.vaccine.2019.09.022

Vaccine

31530468

Evaluation of the Influence of Gastrointestinal Co-Infections on Rotavirus Vaccine Effectiveness in Botswana.

2018

e58-e62

2018 Mar

1532-0987

<p><strong>BACKGROUND: </strong>Studies have demonstrated reduced rotavirus vaccine effectiveness (VE) in resource-limited settings. Enteropathogen co-infections in rotavirus cases have been hypothesized to contribute to the lower vaccine effectiveness in such settings. We sought to determine if co-infections affect rotavirus VE in Botswana.</p>

<p><strong>METHODS: </strong>Between June 2013 and April 2015, children &lt;60 months old, presenting with severe gastroenteritis at four hospitals as part of a national rotavirus surveillance were enrolled. Rotavirus EIA positive samples were tested with an in-house real-time polymerase chain reaction (PCR) panel that detected nine pathogens and a commercial 15 multiplex PCR gastrointestinal pathogen panel (GPP). Co-infection was defined as detection of rotavirus plus one of the five pathogens with the highest attributable fractions for diarrhea. Vaccine status was compared between rotavirus case patients and non-rotavirus "test-negative" controls. Vaccine effectiveness was also calculated restricting cases to those with rotavirus as the only pathogen detected.</p>

<p><strong>RESULTS: </strong>242 children tested rotavirus EIA positive and 368 children were negative. Of the 182 rotavirus EIA-positive samples tested with the GPP assay, co-infections were detected in60 (33%). The overall adjusted 2-dose VE was 59% (95% CI 27-77) in the rotavirus co-infection group and 51% (95% CI -14-79) in the rotavirus mono-infection subgroup. Using in-house multiplex PCR panel, out of 213 rotavirus EIA positive subjects, co-infections were detected in 98 samples (46%). The overall adjusted VE for two doses was 48% (95% CI -2-74) and 62% (95% CI 25-80) in rotavirus mono-infection subgroup.</p>

<p><strong>CONCLUSIONS: </strong>We could not find evidence of an effect of enteric co-infections on the effectiveness of rotavirus vaccine.</p>

10.1097/INF.0000000000001828

29189612