Age-stratified seroprevalence of vaccine-preventable infectious disease in Saravan, Southern Lao People’s Democratic Republic

Abstract

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Susceptibility to Vaccine-Preventable Diseases in Four Districts of Xaysomboun Province, Lao People’s Democratic Republic

“…Seroprotection against measles was as high as 74.6%, but nevertheless not high enough to reach herd immunity (93–95%) [ 31 ]. In children aged 5–10 years, measles seroprotection was only 41.7%, which is in line with only 37.9% MR1 coverage rate of children aged 12–23 months in Xaysomboun province in 2017 [ 11 ] and similar to our previous study in the south of Lao PDR [ 27 ]. Similarly low levels in other settings are associated with high risk of measles outbreaks [ 3 ].…”

“…Seroprotection against rubella in our study was higher than measles in all age groups with 91.2% overall. This is similar to other provinces [ 27 ] and high seroprevalence in children could reflect wild-type rubella circulation [ 32 ], or vaccination—suggesting a difference in immunogenicity between measles and rubella components of the MR vaccine [ 14 , 33 ]. In contrast, the high seroprevalence in adults born before introduction of rubella vaccination in 2011 is likely to be due to rubella virus infection or SIA for younger adults.…”

“…A similar decrease in HBV exposure and chronic infection has been seen in previously endemic countries such as Taiwan and Thailand, following the introduction of the HBV vaccine for newborns and infants [ 26 ]. Compared to our previous study in Saravan, adolescents aged 11–20 years had a similar but slightly higher rate of HBV exposure (4.3% versus 2.8%) [ 27 ], possibly reflecting a later rollout of vaccination in Xaysomboun province at the beginning of HBV vaccine introduction. Our study also found that women between the ages of 21 and 40, when child-birth is common, had a high HBsAg infection rate (12.2–16.7%), emphasizing the importance of the HBV vaccine 24 h after birth and facility-based deliveries.…”

SARS-CoV-2-Related Bat Virus in Human Relevant Models Sheds Light on the Proximal Origin of COVID-19

“… Materials and Methods  Figs. S1 to S11  Tables S1 to S5  References (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) Supplementary Files This is a list of supplementary les associated with this preprint. Click to download.…”

Unexpectedly High Prevalence of Hepatitis C Virus Infection, Southern Laos

“…We nonrandomly selected 753 participants from a larger study ( Appendix ) ( 3 ); participants were persons >5 years of age who were recruited for the larger study while seeking care at the provincial hospital or 1 of 3 district hospitals. Overall, 11.7% (88) participants were HCV antibody seropositive, compared with <2% in previous studies in Laos ( 4 , 5 ) ( Figure ; Appendix ).…”