Adverse events following Quadrivalent HPV vaccination reported in Sao Paulo State, Brazil, in the first three years after introducing the vaccine for routine immunization (March 2014 to December 2016)

Abstract

In March 2014, the Quadrivalent human papilloma virus vaccine (4vHPV) was introduced in the female adolescents vaccination schedule of the National Immunization Program (PNI). A school-based vaccination program was implemented. We conducted a retrospective, descriptive study of the adverse events that took place after HPV vaccination, reported to the Adverse Events Following Immunization (AEFI) Information System in Sao Paulo State, from March 2014 to December 2016. All reports that fit the definitions of the 2014 National Manual on AEFI surveillance were included. AEFI risk was estimated by dividing the number of reports by the number of vaccine doses administered in the period. In the three-year period, 3,390,376 HPV vaccine doses were administered and 465 AEFI reports were registered, with 1,378 signs and symptoms. The reporting rate was 13.72 per 100,000 vaccine doses administered. The reports peaked in the first year of the program. The most frequent AEFI was syncope, with 5.7 reports per 100,000 doses administered, followed by dizziness, malaise, headache and nausea. Overall, 39 AEFI cases (8.4%) were classified as severe , with a reporting rate of 1.15 per 100,000 vaccine doses administered. Most cases were classified as severe because of hospitalization. Among them, there were cases of Guillain-Barré Syndrome, deep vein thrombosis, seizures and miscarriage. All young women recovered without sequelae. We identified five clusters of AEFI reports in four cities; the larger AEFI cluster occurred in the city of Bertioga, in September 2014, involving 13 female adolescents. Our data are in accordance with those from other countries and corroborate the safety of HPV vaccines.

Trends of Adverse Events Following Immunization (AEFI) Reports of Human Papillomavirus Vaccine in the Valencian Community—Spain (2008–2018)

“…As expected when introducing a new vaccine, the AEFI reporting rate for HPV vaccine was very high in 2009 (192.2 per 100,000 doses), and the highest annual number of cases (n = 110; 34.7%) was found in the Valencian Community during the first 10 years of this vaccine's administration. Historical data in some countries [31][32][33] show that initial high levels of AEFI reporting occur each time a new vaccine is introduced, as immunization providers are more likely to report milder, less serious AEFIs for vaccines they are not familiar with, followed by a reduction and stabilization of reporting over time (Weber effect) [34]. This enhanced propensity to report events following newer vaccines increases the sensitivity of the system for detecting signals of serious, rare or previously unknown events.…”

Update on human papillomavirus – Part II: complementary diagnosis, treatment and prophylaxis

“…In 2017, the use was extended to boys, and it is currently recommended for the age range between 11 and 14 years old in this group. 1 , 49 In this age range, regardless of gender, two doses are recommended with a six-month interval between them. In Brazil, the vaccine is also recommended for people living with HIV/AIDS, solid-organ and bone marrow transplant recipients and cancer patients aged 9–26 years old, under medical prescription.…”

“…Especially among the younger population, syncope has been described with the application of other vaccines, blood collection and parenteral administration of medication. 49 Local reactions have also been described, especially with the nonavalent type. 30 The severe adverse effects reported, such as neurological, autoimmune diseases and thromboembolism, have not had a causal association attributed to the HPV vaccines.…”

“… 30 The severe adverse effects reported, such as neurological, autoimmune diseases and thromboembolism, have not had a causal association attributed to the HPV vaccines. 47 , 49 …”

Potential Effects of Human Papillomavirus Type Substitution, Superinfection Exclusion and Latency on the Efficacy of the Current L1 Prophylactic Vaccines

“…Although published work overwhelmingly supports the efficacy of the current prophylactic HPV vaccines, there has been a great deal of publicity and numerous studies carried out on potential vaccine-related adverse events [ 1 , 2 , 3 , 4 ]. The general consensus is that there is no strong evidence that these are increased when compared to other similar adjuvant-containing products although this is still a controversial subject since there are some reports which claim increased adverse reactions in relation to the HPV vaccines [ 2 , 5 ].…”