HBsAg seroprevalence was 1/72 (1.4%) in children aged 5C10 years and it increased to 7/66 (10.6%, aOR 11.98 [1.38C103.87], = 0.02) in age group 21C30 years, 9/45 (20.0%, aOR 30.39 [3.48C264.98], = 0.002) in 31 to 40 year olds, and 10/95 (10.5%, aOR 10.11 [1.23C82.46] = 0.03) in those aged 40 years or older. (78.1%). HBsAg was detected in 9.4% overall and Rabbit Polyclonal to JNKK increased to 20% in ages 31C40 years. Only 13.8% of participants had serology indicative of vaccination (anti-HBs positive, anti-HBc BD-AcAc 2 negative). Seroprotection against measles was 74.6% overall but only 41.7% in children aged 5C10 years. Anti-rubella IgG was 94.2% overall and high in all age groups. Tetanus seroprevalence was only 47.4% overall but significantly higher in females aged 31C40 (75.6%). We suggest strengthening of routine and booster HBV, measles, and tetanus vaccine coverage in Xaysomboun province. = 363). = the minimum sample size was 423. 2.2. Serology Testing Anti-hepatitis B core and surface antibodies (anti-HBc and anti-HBs) were detected by commercial ELISA (Diasorin, Italy) and all anti-HBc positive/anti-HBs unfavorable samples were tested for HBsAg (Diasorin, Italy), which would account for the majority of HBsAg positive participants . HBsAg positive samples were defined as acute or chronic contamination, anti-HBc positive as previously uncovered and anti-HBc unfavorable, anti-HBs positive as previously vaccinated. Measles, rubella, and tetanus ELISA BD-AcAc 2 results were interpreted according BD-AcAc 2 to the manufacturer (Euroimmun, Germany). Thus, anti-measles IgG titers 200 IU/L were considered unfavorable, titers between 200 and 275 IU/L as borderline, and titers 275 IU/L as positive. Anti-rubella IgG titers 8 IU/mL were considered unfavorable, titers between 8 and 11 IU/mL as borderline, and a titers 11 IU/mL as positive. For anti-tetanus IgG, titers 0.1 IU/mL were defined as insufficient immunity: immediate boost recommended, those from 0.1 to 0.5 IU/mL as low immunity: immediate boost recommended, 0.5 to 1 1.1 IU/mL as sufficient immunity: booster recommended in 2C5 years, 1.1 to 5.0 IU/mL as sufficient immunity: booster recommended in 5C10 years and those above 5.0 IU/mL: sufficient immunity: booster recommended in approximately 10 years. Protective anti-tetanus antibody titers were defined as those above 0.5 IU/mL. 2.3. Statistical Analysis The completeness and correctness of data were checked before data analysis. All data were analyzed with STATA version 14. Descriptive data were calculated for categorical variables and the means with minimum, maximum, and standard deviation (SD) for continuous variables. Bivariate analysis was applied to determine the association between the independent variables (HBV, tetanus, measles, and rubella serostatus) and the dependent variables (sociodemographics). All variables with value 0.2 in bivariate model were included for multivariable analysis. Adjusted odds ratios (aOR) were described. The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Internal Review Board of Institut Pasteur du Laos and the Lao National Ethics Committee for Health Research (Ref. number 010/NEHCR/2020). 3. Results 3.1. Population Characteristics Twelve people were excluded due to refusal to participate from fear of needles and were replaced by 12 other randomly selected participants. Six participants withdrew from the study after consent, due to fear of the blood draw, and one withdrew due to difficulty to draw blood. Due to COVID-19 restrictions, the study could not be conducted in Anouvong District. Thus, the total number of participants was 363. The median age was 25 years (range 5 to 80), 61.2% were female and 42.9% were Hmong. Most participants followed animism (66.9%) and 57.3% were married. 78.5% of the participants were born at home and most (82.9%) had a family monthly income of 1 1 million to 3 million kips (Table 1). 3.2. Hepatitis B Virus (HBV) Anti-HBc antibody seroprevalence, indicating HBV exposure, was 204/363 (56.2%) overall. There was no significant difference between male and female participants. Exposure was 10/72 (13.9%) in the 5C10-year-old age group but was found to be significantly higher in all older age groups after multivariable analysis, with the highest at 39/45 (86.7%) in those aged 31C40 years (aOR 21.33 [5.26C86.53] 0.001). Participants from Thathom district had higher anti-HBc seroprevalence than those from Longxarn (61.9% and 47.3%; aOR 3.16 [1.54C6.49] = 0.002) (Table 2 and Supplementary Table S1). Table 2 Hepatitis B virus serology by age group and sex. Anti-HBc positive/anti-HBs unfavorable samples were screened for HBsAg. All other samples were assumed to be HBsAg unfavorable . = 0.04). HBsAg seroprevalence was 1/72 (1.4%) in children aged 5C10 years and it increased to 7/66 (10.6%, aOR 11.98 [1.38C103.87], = 0.02) in age group 21C30 years, 9/45 (20.0%, aOR 30.39 [3.48C264.98], = 0.002) in 31 to 40 year olds, and 10/95 (10.5%, aOR 10.11 [1.23C82.46] = 0.03) in those aged 40 years or older. In addition, participants from Thathom district had a higher HBsAg seroprevalence (16/105, 15.2%) compared with BD-AcAc 2 Longxarn (6/93, 6.4%; aOR 3.15 [1.13C8.79] = 0.02]) (Physique 1, Table 2 and Supplementary Table S1). Open in a separate window Physique 1 Age-stratified.