Results of long-term studies on diphtheria-tetanus-pertussis immunization
Scientists at the Charité – Universitätsmedizin Berlin evaluated long-term scientific surveys and identified a relationship between vaccination trends and rates of sudden infant death syndrome. Over the past 40 years, immunization rates in the United States have fluctuated as a function of societal trends. The sudden infant death syndrome rate was found to be inversely proportional to the overall vaccination coverage for diphtheria-tetanus-pertussis (whooping cough). The results of this study have been published in the professional journal BMC Pediatrics*.
While the incidence of sudden infant death syndrome (SIDS) continues to decline, it remains one of the main causes of infant mortality worldwide. Its cause is still unknown and newborns are particularly vulnerable to SIDS during their first year of life. It is precisely during this period that immunizations for whooping cough, diphtheria, tetanus, polio or Haemophilus influenzae are generally recommended. Contrary to fears voiced by 'vaccination skeptics', i.e. that immunizations are associated with complications or an increased risk of SIDS, the data published by vaccination authorities and health centers in the United States reveal quite a different picture: "Our study shows that classical immunizations administered during infancy to prevent whooping cough, diphtheria, tetanus, polio or Haemophilus influenzae are not associated with an increased risk for SIDS. They may even have a protective effect", says Prof. Dr. Jacqueline Müller-Nordhorn, Head and Spokesperson of the Berlin School of Public Health (BSPH).
In their search for any significant changes in the mortality rate due to SIDS, the researchers included studies on sleeping positions of infants during the same time period. In the current study, the temporal relationship between the recommendations for vaccinations and the prevailing societal trends become particularly clear. Vaccination coverage declined in the United States in the 1970s and 1980s in reaction to feelings of uncertainty among the population. At the same time, the mortality rate due to SIDS increased by 27% between 1968 and 1971, and by 47 percent between 1971 and 1974. The rate of SIDS subsequently declined again, for example by eight percent between 1991 and 2001. The trend is clear: an increase in vaccination coverage lowers the incidence of sudden infant death syndrome. A 10-percent higher coverage in a population, the example here being the United States, lowers the rate of sudden infant death syndrome by nearly 10 percent.
In Germany as well, concerns and fears also shape how parents decide for or against vaccinating their children, as demonstrated in the ongoing debate concerning the measles vaccination in Germany. One example of this anxiety is a supposed link between the measles vaccination and the occurrence of autism, a hypothesis which has been shown to be false on multiple occasions. In the case of whooping cough, the falsely propagated risk of brain damage resulted in a decline in vaccination rates during the 1970s and 1980s. Medical studies carried out over the subsequent years did not reveal such risk. Vaccination coverage tend to fluctuate as a function of public opinion and recommendations given by experts. "In certain countries including Germany the whooping cough vaccination was even removed from the list of recommended vaccinations for a period of time and was only reintroduced in 1991", according to Müller-Nordhorn. The figures show that the reintroduction of the whooping cough vaccination has been associated with a drop in the rate of sudden infant death syndrome. For all immunizations given during childhood it is important to not only consider the "whether", but also the "when" to ensure that such vaccinations are given within the recommended time frame. "It would be particularly tragic if parents delayed vaccinations to protect their children, but in doing so might induce the opposite effect", explains Müller-Nordhorn.
*Jacqueline Müller-Nordhorn, Chih-Mei Hettler-Chen, Thomas Keil, Rebecca Muckelbauer. Association between sudden infant death syndrome and diphtheria-tetanus-pertussis immunisation: an ecological study. BMC Pediatrics, Jan. 2015. doi: 10.1186/s12887-015-0318-7
Prof. Dr. Jacqueline Müller-Nordhorn
Head, Berlin School of Public Health (BSPH)
Charité – Universitätsmedizin Berlin
t: +49 30 450 570 872
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