Diphtheria Toxoid Vaccine Effectiveness: A Case‐Control Study in Russia

Abstract

Prior to the completion of this and other studies, low effectiveness of diphtheria toxoid-containing vaccine was suspected to be a major contributing factor to the diphtheria epidemic that began in the Russian Federation in 1990. A vaccine effectiveness study was done in Moscow by enrolling physician-diagnosed cases and 10 control subjects per case. Controls were matched to cases by age (+/-3 months) and clinic registration. Vaccination history was abstracted from a standardized form for case-patients and from clinic vaccination records for control subjects. Two hundred seventeen case-patients and 2169 matched controls were included in the study. Most controls (92%) had received three or more doses of a diphtheria toxoid vaccine, compared with 72% of case-patients. The vaccine effectiveness for three or more doses was 97% (95% confidence interval: 94.3-98.4). Low vaccine effectiveness was not a contributing factor to the diphtheria epidemic in the Russian Federation. To control and prevent diphtheria epidemics, it is necessary to achieve and maintain high vaccination coverage with three or more doses of diphtheria toxoid among adults and children.

Persistence of Diphtheria, Hyderabad, India, 2003–2006

“…Similar phenomena were observed in countries where diphtheria reemerged after successful con- trol with vaccination (2,7). Several studies have reported vaccine effi cacies ranging from 95% to 98% for 3 doses and from 90% to 99.9% for 5 doses (8,9). Two factors may explain the lower effi cacy observed in our study.…”

How Many Doses of Diphtheria Toxoid Are Required for Protection in Adults? Results of a Case‐Control Study among 40‐ to 49‐Year‐Old Adults in the Russian Federation

“…In the 1980s, Russian studies demonstrated that 190% of children who had received four doses of diphtheria toxoid in the first 2 years of life had levels of antibody consistent with protection against disease [18,19]. Studies in the 1990s among children confirmed the effectiveness of vaccination with Russian-produced vaccine against diphtheria [20]. A study done in Ukraine using Russian-produced diphtheria toxoid found that 89% of 18-to 67-year-old adults with unknown primary immunization history had antibody levels 10.1 IU/mL 1 month after revaccination with a single dose [6].…”

Successful Control of Epidemic Diphtheria in the States of the Former Union of Soviet Socialist Republics: Lessons Learned

“…In Vladivostok, at UNIVERSITY OF ARIZONA on June 1, 2015 http://jid.oxfordjournals.org/ Downloaded from a lower level of immunity was found among children who received Td in the primary series compared with those who had received DTP [33]. In a vaccine-effectiveness study performed in Moscow, receipt of four doses (usually reflecting a primary series with DTP) was significantly more effective than three doses (primary series with Td) [34].…”

“…However, case-control studies in Ukraine in 1992 and in Moscow in 1993 demonstrated that receipt of three or more doses of Russian-manufactured diphtheria toxoid was highly effective in preventing disease in children [34,41]. In these studies, the effectiveness of three doses of any diphtheria toxoid-containing vaccine exceeded 95%.…”