Adverse cardiorespiratory events following primary vaccination of very low birth weight infants [Eventos cardiorrespiratórios adversos após vacinação primária de recém-nascidos de muito baixo peso]

Objective: to examine the relationship between primary vaccination of preterm infants and prevalence ratios of associated factors for unwanted cardiorespiratory events,following the recommendation of the centers for disease control and prevention advisory committee on immunization practices for immunization of preterm infants at 2 months of chronological age. methods: two-year retrospective study of very low birth weight infants receiving their primary vaccination. major cardiorespiratory events,such as apnea,bradycardia,spo2 desaturation,and minor adverse events,such as temperature instability,poor handling and local reactions,were recorded. prevalence ratio with 95% confidence interval for associated factors between infants with and without cardiorespiratory events was calculated. results: eighty neonates were studied (median [range] birth weight 970 g [428-1,490]),gestational age of 27.4 weeks (23.3-33). adverse reactions occurred in 35 (44%) patients: minor events in 19 (24%),major events in 28 (35%). infants with major events had significantly lower gestational age (p = 0.008) and a higher incidence of bronchopulmonary dysplasia (71% vs. 48%; p < 0.05). in very low birth weight infants with major events,o2 desaturations before vaccination were 3.40 (1.41-8.23) times higher and treatment with methylxanthines for apnea and bradycardia syndrome was 8.05 (2.50-25.89) times higher compared to infants without major events. conclusion: major cardiorespiratory events occurred in over 1/3 of all very low birth weight infants after vaccination. associated factors were low gestational age,bronchopulmonary dysplasia,methylxanthine treatment,and persisting o2 desaturations before vaccination. primary vaccination of very low birth weight infants should be performed under continuous monitoring of vital parameters. copyright © by sociedade brasileira de pediatria.