Seroprevalence of anti-tetanus antibodies in mothers and cord blood and associated factors in health-care settings in Lao People's Democratic Republic

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

Xaysomboun province has some of the lowest health indicators in Lao People’s Democratic Republic (PDR). This cross-sectional study aimed to determine the vaccination, susceptibility and exposure status of the population to hepatitis B virus (HBV), measles, rubella, and tetanus. Participants aged 5 years and older were randomly selected from four districts. From each enrolled participant, demographic data and 5 mL of blood sample were taken. HBV surface antigen (HBsAg) and antibodies against HBV, measles, rubella, and tetanus were detected by ELISA. A total of 363 participants (age 5 to 80 years) were included. HBV exposure, as determined by anti-HBV core (anti-HBc) antibodies, was 56.2% overall, and was significantly higher among those aged ≥21 years (78.1%). HBsAg was detected in 9.4% overall and increased to 20% in ages 31–40 years. Only 13.8% of participants had serology indicative of vaccination (anti-HBs positive, anti-HBc negative). Seroprotection against measles was 74.6% overall but only 41.7% in children aged 5–10 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 31–40 (75.6%). We suggest strengthening of routine and booster HBV, measles, and tetanus vaccine coverage in Xaysomboun province.

Tetanus vaccination in pregnant women: a systematic review and meta-analysis of the global literature

OBJECTIVES

This study aimed to determine the effect of several factors on the uptake of tetanus vaccination in pregnant women.

STUDY DESIGN

This is a systematic review and meta-analysis of the global literature.

METHODS

The search strategy was carried out in the EMBASE and MEDLINE (Pubmed) databases, without language restrictions. The databases were searched from the beginning until May 2020. Fixed and random effect models were applied according to the methodological heterogeneity between the included studies. The I² test was performed to assess the magnitude of the heterogeneity. The results were presented as a grouped odds ratio (OR) with a 95% confidence interval (CI) and a significance level of 0.05.

RESULTS

The initial search strategy generated 14,349 original articles. In total, 31 studies met all inclusion criteria and 20 articles were included in the meta-analysis. The grouped and subgroup analyses showed a significant association between tetanus vaccination and the following factors: higher number of prenatal visits (OR: 2.00; 95% CI: 1.17-3.42), higher maternal age (OR: 1.24, 95% CI: 1.02-1.50), being single (OR: 1.41; 95% CI: 1.20-1.65), professional vaccine guidance (OR: 9.00; 95% CI: 1.81-44.75) and uptake of influenza vaccine (OR: 5.87; 95% CI: 1.39-24.73).

CONCLUSIONS

The uptake of tetanus vaccine in pregnant women is associated with various factors. The identification of these factors is an important step towards the implementation of public health strategies aimed at improving immunisation against tetanus in pregnant women.

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

BACKGROUND

Lao People's Democratic Republic has frequent outbreaks of vaccine-preventable diseases (VPD). This study aimed to determine susceptibility and exposure to VPD in Saravan, a rural province with high ethnic diversity and some of the poorest health indicators nationwide.

METHODS

Patients from three district hospitals and one provincial hospital were enrolled. Serum was tested by ELISA for IgG against hepatitis B virus (HBV), tetanus, diphtheria, measles, and rubella.

RESULTS

The study enrolled 2463 participants aged 5-90 years. Exposure to HBV was 33.2% and increased with age up to 62.4% of those aged >50 years. HBV surface antigen prevalence was 5.7% in males and 2.4% in females; 9.9% had serology compatible with vaccination. Seroprevalence of protective anti-tetanus antibodies was 46.3% overall. Protective anti-diphtheria seroprevalence was 40.5%. Anti-measles seroprevalence increased from 16.7% in those aged 5-10 years to 97.7% in those aged >50 years. Anti-rubella seroprevalence was 93.0% overall. There were differences in seroprevalences between sex, districts and ethnicity.

CONCLUSIONS

Routine infant vaccination needs strengthening in order to close the immunity gaps. High burden of HBV infection should be addressed by increasing birth dose vaccine coverage. Regional and ethnic differences need to be investigated to enable a targeted approach to vaccination.

Immunity status against tetanus in young migrants: a seroprevalence study

BACKGROUND AND AIM OF THE WORK

Thanks to the highly effective vaccine, tetanus became sporadic in high-income countries with well-established primary childhood immunization programs, but it is common in low-income countries. The migrants, leaving countries with poor immunization programs or where vaccinations have been interrupted, may represent a new risk group for tetanus in host countries. A seroprevalence study was conducted to estimate the immunological status against tetanus in young migrants without vaccination documentation.

METHODS

After a careful assessment by vaccination services of the Local Health Authority, all migrants recently arrived in Italy were included in the serosurvey. Titers of anti-tetanus toxoid were measured using a commercial ELISA kit. Subjects were stratified by age and by WHO region. Antibody titers <0.10 IU/ml were considered to be seronegative, between 0.10 and 1.00 IU/ml as intermediate protection, and >1.00 IU/ml high protection.

RESULTS

From January 2004 to December 2019, 2,326 blood samples were collected. Mean age was 13.9 years with no differences between WHO regions. The percentage of the subjects without protective antibodies was 22.3%, with an intermediate level was 45.2%, with high titer was 32.5%. Among migrant coming from African and Eastern Mediterranean WHO regions, the highest percentages of seronegative titers and, at the same time, the low percentages of high protective levels were found. Titers decreased with age.

CONCLUSIONS

The significant proportion of seronegative migrants and the decrease of protective titers increasing age, confirm the importance of the evaluation of the immunological status to employ the appropriate vaccination strategy.