Low postpartum rubella vaccination rates in high-risk women, Miami, Florida, 2001

Is birth cohort 1985/9-1990/8 a susceptibility window for congenital rubella syndrome in Taiwan?

OBJECTIVE

The worldwide prevalence of congenital rubella syndrome has drastically decreased after the uptake of vaccine to prevent the infection. However, outbreaks have occurred in some countries due to their own vaccination policies, and this phenomenon has not yet been investigated in Taiwan. Our study aims to fill this gap.

MATERIALS AND METHODS

We constructed an analytical database containing 10,824 pregnant women at the Taipei City Hospital, Taipei, Taiwan from January 2004 to July 2012. They were categorized into five birth cohorts according to the different vaccination programs in Taiwan: those born before 1971; those born between September 1971 and August 1976; between September 1976 and August 1979; between September 1979 and August 1985; and between September 1985 and August 1990. Differences of the seronegative rate and titers were compared using the Chi-square and Kruskal-Wallis tests among the five cohorts.

RESULTS

The seronegative rates for the five cohorts were 15.00%, 4.07%, 2.88%, 4.21%, and 10.98%, respectively, and were statistically significant different (p < 0.001). The first and fifth cohorts were higher than the average of seronegativity (5%). The mean of log transformed titers were 3.69 IU/mL, 4.22 IU/mL, 4.22 IU/mL, 4.05 IU/mL, and 3.44 IU/mL, which were statistically significant different (p<0.001). Our study also found that the equivocal rates (7.58%) were the highest in the cohort born between September 1985 and August 1990, among those who had been vaccinated. Our study showed that women younger than 27 years had a lower geometric mean titer of antibody titer than the average (60.60 IU/mL).

CONCLUSION

The previous vaccination policy in Taiwan has created a susceptibility window for rubella and congenital rubella syndrome over the past decades. We recommend having the antibody test before pregnancy for women born between September 1985 and August 1990, and implement a catch-up vaccine for those who were either seronegative or equivocal to prevent reinfection during their childbearing period.

Effects of campaign for postpartum vaccination on seronegative rate against rubella among Japanese women

BACKGROUND

Japan experienced two rubella outbreaks in the past decade (2004 and 2012-2013), resulting in 10 and 20 infants with congenital rubella syndrome (CRS), respectively. This study was performed to determine whether the seronegative rate was lower in multiparous women than in primiparous women in Japan.

METHODS

Hemagglutination inhibition (HI) test results during pregnancy were analyzed retrospectively in 11048 primiparous and 9315 multiparous women who gave birth at six hospitals in northern Japan in the 5-year study period (January 2008 through December 2012). Women with HI titer <  1:8 were defined as susceptible to rubella.

RESULTS

The seronegative rate was significantly lower in multiparous than primiparous women aged 30 - 31 years (2.3% [22/967] vs. 4.5% [66/1454], P  =  0.0036), 36 - 37 years (3.4% [55/1601] vs. 5.7% [79/1389], P  =  0.0030), and overall women (3.8% [350/9315] aged 34.7  ±  5.2 vs. 5.4% [597/11048] for 33.2  ±  5.9, P  <  0.001). The susceptible fraction size did not differ largely according to hospital, ranging from 3.5% to 6.3%. Those for each year did not change markedly; 4.5% [150/3369], 5.2% [221/4268], 4.4% [195/4412], 4.6% [186/4056], and 4.6% [195/4258] for 2008, 2009, 2010, 2011, and 2012, respectively. Those for teenagers were consistently high: 22.7% [5/22], 20.7% [6/29], 20.6% [7/34], 13.0% [3/23], and 23.5% [4/17] for 2008, 2009, 2010, 2011, and 2012, respectively.

CONCLUSIONS

The seronegative rate was significantly lower in multiparous than primiparous women. However, Japanese rubella vaccination programs were insufficient to eliminate CRS.

Positive rates for rubella antibody in pregnant women and benefit of post-partum vaccination in a Japanese perinatal center

AIM

This study of pregnant women was undertaken to clarify their immune status for rubella and to evaluate the efficacy of, and adverse reaction to, post-partum rubella vaccination.

METHODS

We determined the levels of both rubella antibody by hemagglutination inhibition test and IgM antibody by enzyme-linked immunosorbent assay in the first gestational trimester and surveyed the positive rates for rubella antibody in pregnant women at our perinatal center; we recommended post-partum vaccination for women with poor immune status. We also evaluated the effectiveness of the vaccine and any adverse reaction.

RESULTS

Among 2741 pregnant women, 185 cases (6.7%) were seronegative for rubella virus. This rate was especially high (12.4%) in the population who had opted out of the vaccination because of a change in Japanese government policy. A total of 30 cases (1.1%) were positive or false-positive for IgM antibody, but no congenital rubella syndrome (CRS) developed. The seropositive rate was 93.3% in total, but this figure includes those who required post-partum vaccination (558 cases or 20.3%) because their titers were 16x or lower. Among 145 cases who received post-partum rubella vaccine, no severe adverse reaction was detected, and in all 37 cases with hemagglutination inhibition antibody titers of 8x or lower, the efficacy rate was 100%.

CONCLUSIONS

It is necessary to appropriately evaluate the CRS risk. Also, we need to emphasize the importance and safety of post-partum rubella vaccination in Japan.

Medical practices for prevention of perinatal infections in Puerto Rico

Recommendations for screening for maternal infections and interventions to prevent disease in the fetus or newborn have been in place in Puerto Rico for more than 10 years. However, compliance with these recommendations has not been widely documented. We evaluated compliance with rubella/hepatitis B prenatal screening and vaccination recommendations, assessed hospital screening practices for syphilis and HIV, and determined risk factors for suboptimal prenatal care. Records of a random, stratified sample of 2003 pregnant women delivering in eight maternity hospitals in Puerto Rico in 2002 were reviewed. Obstetric prenatal and postnatal records were also reviewed when rubella/hepatitis B surface antigen (HBsAg) screening was not available at the hospital, and to document rubella postpartum vaccination (PPV). Prenatal screening rates were 98.4% for rubella and 98.8% for HBsAg. Overall, 5.4% [95% CI 4.4, 6.5] of women were susceptible to rubella. No eligible women received rubella PPV at the hospital and only 1.5% had documented rubella vaccine prescription at the obstetric records. Only one woman was found to be HBsAg positive and her newborn was adequately treated. However, only 0.9% newborns born to mothers with unknown HBsAg status received hepatitis B vaccine. Screening was documented in 85.7% of the hospital records for HIV and 87.9% for syphilis. Suboptimal prenatal care was more likely among teenagers, low-educated women, and women with >3 previous pregnancies. Screening rates for rubella and hepatitis B were high; however, implementation of recommendations for prevention of rubella and hepatitis B needs to be improved.