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Immunization During Pregnancy Against Poliomyelitis and Influenza in Relation to Childhood Malignancy
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1973
Year
ImmunodeficienciesImmunologyVaccine HesitancyImmunotherapyMaternal ImmunizationMicroscopic TumoursLive Polio VaccinePolio VaccinePregnancy Against PoliomyelitisPublic HealthPolioVaccine SafetyMaternal HealthVaccinationChildhood MalignancyPediatricsVaccine EfficacyInfluenza VaccineMedicine
The authors followed 50,897 pregnancies from 1959–1966, recording maternal poliomyelitis and influenza immunizations and viral infections, and ascertained childhood malignancies through first‑year clinical follow‑up and four‑year mortality data. Vaccinated mothers had a higher childhood malignancy rate (7.6 vs 3.1 per 10,000), especially when immunized in the first four lunar months (13.2 per 10,000), with clustering of vaccine timing among affected children; neural tumors were more common in exposed children (3.8 vs 0.3 per 10,000), but after excluding microscopic tumors the rates dropped to 6.5 vs 2.8 per 10,000, and no excess malignancies were seen with live polio, influenza, or viral infections.
In a follow-up study of 50,897 pregnancies, poliomyelitis and influenza immunizations, and viral infections were evaluated as possible risk factors for the development of malignancies in the offspring born between 1959 and 1966. Ascertainment of malignancies was based on clinical follow-up during the first year of life and on mortality experience covering the first four years of life. In 18, 342 children whose mothers were vaccinated during pregnancy with killed polio vaccine there were 14 malignancies (7.6 per 10,000) and in 32, 555 non-exposed children there were 10 (3.1 per 10,000). In the vaccinated group, nine malignancies occurred in children whose mothers were immunized during the first four lunar months of pregnancy (13.2 per 10,000). Time clustering of administration of the vaccine was evident in mothers whose children developed malignancies. There were seven tumours derived from neural tissue in the exposed children (3.8 per 10,000) and one in the non-exposed children (0.3 per 10,000). Elimination of three microscopic tumours reduced the overall rates in the exposed and non-exposed groups to 6.5 and 2.8 per 10,000, respectively. There was no evidence of an excess of malignancies in children exposed in utero to attenuated live polio vaccine, to influenza vaccine, or to spontaneous viral infections.