Near Real-Time Surveillance to Assess the Safety of the 9-Valent Human Papillomavirus Vaccine.

BACKGROUND AND OBJECTIVES: Human papillomavirus is the most common sexually transmitted infection in the United States and causes certain anogenital and oropharyngeal cancers. The 9-valent human papillomavirus vaccine (9vHPV) provides protection against additional types not included in the quadrivalent vaccine. We conducted near real-time vaccine safety surveillance for 24 months after the vaccine became available in the Vaccine Safety Datalink. METHODS: Immunizations and adverse events were extracted weekly from October 2015 to October 2017 from standardized data files for persons 9 to 26 years old at 6 Vaccine Safety Datalink sites. Prespecified adverse events included anaphylaxis, allergic reaction, appendicitis, Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, injection site reaction, pancreatitis, seizure, stroke, syncope, and venous thromboembolism. The observed and expected numbers of events after 9vHPV were compared weekly by using sequential methods. Both historical and concurrent comparison groups were used to identify statistical signals for adverse events. Unexpected signals were investigated by medical record review and/or additional analyses. RESULTS: During 105 weeks of surveillance, 838 991 doses of 9vHPV were administered. We identified unexpected statistical signals for 4 adverse events: appendicitis among boys 9 to 17 years old after dose 3; pancreatitis among men 18 to 26 years old; and allergic reactions among girls 9 to 17 years old and women 18 to 26 years old after dose 2. On further evaluation, which included medical record review, temporal scan analysis, and additional epidemiological analyses, we did not confirm signals for any adverse events. CONCLUSIONS: After 2 years of near real-time surveillance of 9vHPV and several prespecified adverse events, no new safety concerns were identified.

Determinants of human papillomavirus vaccine attitudes: an interview of Wisconsin parents.

BACKGROUND: Parental attitudes play a key role in their decisions to vaccinate adolescents against the human papillomavirus (HPV). Little is known, however, about the formative experiences that shape parents' attitudes about the HPV vaccine. METHODS: We conducted semi-structured interviews with 25 parents of 11-17 year old adolescents in Wisconsin who changed their HPV vaccine attitudes (per prior surveys) over one year. A modified grounded theory approach was then used to generate primary themes of attitudinal determinants. RESULTS: Participants were predominately mothers. We identified three major themes that shaped parents' HPV attitudes: (1) the perceived likelihood of the HPV vaccine preventing cancer, (2) agency in adolescence and gauging their adolescent child's intent for sexual activity, (3) the credibility of HPV vaccine information sources. General messaging around cancer prevention did not always supersede some parents' concerns about the vaccine's perceived link to sexual activity. Parents often viewed their adolescent child's feelings about the HPV vaccine as a gauge of their (child's) intent for sexual activity. Interviewees felt a sense of responsibility to educate themselves about the HPV vaccine using multiple sources and particularly looked to their medical provider to filter conflicting information. CONCLUSIONS: More family-specific (vs. disease-prevention) messaging and recommendations may be needed in the clinical environment to sway some parents' negative attitudes about the HPV vaccine. Future research should explore additional strategies to improve HPV vaccine attitudes, such as situating the vaccine in the context of a monogamous lifestyle that many parents wish to impart to their children.

Association between parent attitudes and receipt of human papillomavirus vaccine in adolescents.

BACKGROUND: Human papillomavirus (HPV) vaccine coverage rates remain low. This is believed to reflect parental hesitancy, but few studies have examined how changes in parents' attitudes impact HPV vaccine uptake. This study examined the association between changes in parents' vaccine attitudes and HPV vaccine receipt in their adolescent children. METHODS: A baseline and 1-year follow-up survey of HPV vaccine attitudes was administered to parents of 11-17 year olds who had not completed the HPV vaccine series. Changes in attitudinal scores (barriers, harms, ineffectiveness, and uncertainties) from the Carolina HPV Immunization Attitudes and Beliefs Scale were assessed. Two outcomes were measured (in parents' adolescent children) over an 18-month period and analyzed using multivariable regression; receipt of next scheduled HPV vaccine dose and 3-dose series completion. RESULTS: There were 221 parents who completed the baseline survey (11% response rate) and 164 with available follow-up data; 60% of their adolescent children received a next HPV vaccine dose and 38% completed the vaccine series at follow-up. Decrease in parents' uncertainties was a significant predictor of vaccine receipt, with each 1-point reduction in uncertainties score associated with 4.9 higher odds of receipt of the next vaccine dose. Higher baseline harms score was the only significant predictor of lower series completion. CONCLUSIONS: Reductions in parents' uncertainties appeared to result in greater likelihood of their children receiving the HPV vaccine. Only baseline concerns about vaccine harms were associated with lower series completion rate. Education for parents should emphasize the HPV vaccine's safety profile.

Risk of venous thromboembolism following influenza vaccination in adults aged 50years and older in the Vaccine Safety Datalink.

BACKGROUND: Influenza-like illness and inflammation are known risk factors for venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE). However, few studies have characterized the risk of VTE following influenza vaccination. We examined VTE risk after vaccination in adults 50years old and older within the Vaccine Safety Datalink (VSD). METHODS: We used the self-controlled case series method to determine the risk of VTE among age-eligible adults who received influenza vaccine (with or without pandemic H1N1) and experienced a VTE during the months of September through December in 2007 through 2012. Presumptive VTE cases were identified among VSD participants using diagnostic codes, diagnostic tests, and oral anticoagulant prescription. Potential cases were validated by medical record review. The VTE incidence rate ratio was calculated among confirmed cases for the risk window 1 to 10days after vaccination relative to all other person-time from September through December. RESULTS: Of the 1,488 presumptive cases identified, 508 were reviewed, of which 492 (97%) were confirmed cases of VTE. The analysis included 396 incident, confirmed cases. Overall, there was no increased risk of VTE in the 1 to 10days after influenza vaccination (IRR=0.89, 95% CI 0.69-1.17) compared to the control period. Results were similar when all person-time was censored before vaccination. A post hoc analysis showed an increased risk among current tobacco smokers (IRR=2.57, 95% CI 1.06-6.23). No clustering of VTE was observed in the 1-42days after vaccination. DISCUSSION: Overall, there was no evidence that inactivated influenza vaccine was associated with VTE in adults ≥50years old. An increased risk was found among current smokers in a post hoc analysis. These findings are consistent with previous research and support the safety of annual vaccination in this population.