Monitoring the safety of quadrivalent human papillomavirus vaccine: Findings from the Vaccine Safety Datalink

Safety profile assessment of HPV4 and HPV9 vaccines through the passive surveillance system of the Veneto Region (Italy) between 2008 and 2022: A 15-year retrospective observational study

In Veneto Region, HPV vaccine has been actively offered to 12 year-old females since 2008, and to 12 year-old males since 2015. The study aims to analyze the safety profile of HPV4v and HPV9v vaccines and perform a case-by-case review of conditions of interest. Spontaneous reports related to HPV uploaded to the database of the Regional Pharmacovigilance Center between 2008-2022 were included. HPV vaccine doses administered until April 2022 in the Veneto Region were considered to calculate the reporting rate (RR). Potential "safety concerns" examined as conditions of interest were included through Standardized MedDRA or preferred terms searching queries. The level of diagnostic certainty was evaluated as per the Brighton Collaboration case definition criteria. A total of 637 reports and 1316 Adverse Events Following Immunizations (AEFI) were retrieved: 469 for HPV4v (73.6 %) and 168 for HPV9v (26.4 %). Serious reports were 71 (11.1 %): 49 (10.4 %) for HPV4v and 22 (13.1 %) for HPV9v. The RR for serious events between 2008-2022 was 6.9/100,000 administered doses, with no differences by vaccine type. Females and adults showed higher overall RR compared to males and to children and adolescents (p < 0.001), this result was confirmed by stratifying analysis by vaccine type. One case of Guillain Barré syndrome, anaphylactic shock, thrombocytopenia, Henoch Schoenlein purpura and four generalized seizures were reviewed. Vaccinovigilance data from the Veneto Region reaffirm a good safety profile for HPV vaccination and found no vaccine-related unexpected events. Such a detailed analysis may assist healthcare providers to advocate properly for HPV vaccination.

The Role of Scientific Research in Human Papillomavirus Vaccine Discussions on Twitter: Social Network Analysis

BACKGROUND

Attitudes toward the human papillomavirus (HPV) vaccine and accuracy of information shared about this topic in web-based settings vary widely. As real-time, global exposure to web-based discourse about HPV immunization shapes the attitudes of people toward vaccination, the spread of misinformation and misrepresentation of scientific knowledge contribute to vaccine hesitancy.

OBJECTIVE

In this study, we aimed to better understand the type and quality of scientific research shared on Twitter (recently rebranded as X) by vaccine-hesitant and vaccine-confident communities.

METHODS

To analyze the use of scientific research on social media, we collected tweets and retweets using a list of keywords associated with HPV and HPV vaccines using the Academic Research Product Track application programming interface from January 2019 to May 2021. From this data set, we identified tweets referring to or sharing scientific literature through a Boolean search for any tweets with embedded links, hashtags, or keywords associated with scientific papers. First, we used social network analysis to build a retweet or reply network to identify the clusters of users belonging to either the vaccine-confident or vaccine-hesitant communities. Second, we thematically assessed all shared papers based on typology of evidence. Finally, we compared the quality of research evidence and bibliometrics between the shared papers in the vaccine-confident and vaccine-hesitant communities.

RESULTS

We extracted 250 unique scientific papers (including peer-reviewed papers, preprints, and gray literature) from approximately 1 million English-language tweets. Social network maps were generated for the vaccine-confident and vaccine-hesitant communities sharing scientific research on Twitter. Vaccine-hesitant communities share fewer scientific papers; yet, these are more broadly disseminated despite being published in less prestigious journals compared to those shared by the vaccine-confident community.

CONCLUSIONS

Vaccine-hesitant communities have adopted communication tools traditionally wielded by health promotion communities. Vaccine-confident communities would benefit from a more cohesive communication strategy to communicate their messages more widely and effectively.

Incidence of Adolescent Syncope and Related Injuries Following Vaccination and Routine Venipuncture

PURPOSE

Vaccination is associated with syncope in adolescents. However, incidence of vaccine-associated syncope and resulting injury, and how it compares to syncope incidence following other medical procedures, is not known. Here, we describe the incidence of syncope and syncope-related injury in adolescents following vaccination and routine venipuncture.

METHODS

We identified all Kaiser Permanente Northwest members ages 9-18 years with a vaccination or routine venipuncture and a same-day International Classification of Diseases diagnosis of syncope from 2013 through 2019. All cases were chart reviewed to establish chronology of events (vaccination, venipuncture, syncope, and injury, as applicable) and to attribute cause to vaccination or venipuncture. Incidence rates for vaccine-associated and venipuncture-associated syncope were calculated overall, by sex and age group. Syncope events resulting in injury were assessed for each event type.

RESULTS

Of 197,642 vaccination and 12,246 venipuncture events identified, 549 vaccination and 67 venipuncture events had same-day syncope codes. Chart validation confirmed 59/549 (10.7%) events as vaccine-associated syncope, for a rate of 2.99 per 10,000 vaccination events (95% confidence interval (CI): 2.27-3.85) and 20/67 (29.9%) events as venipuncture-associated syncope, for a rate of 16.33 per 10,000 venipuncture events (95% CI: 9.98-25.21). The incidence rate ratio of vaccine-associated to venipuncture-associated syncope events was 0.18 (95% CI: 0.11-0.31). The incidence of vaccine-associated syncope increased with each additional simultaneously administered vaccine, from 1.51 per 10,000 vaccination events (95% CI: 0.93-2.30) following a single vaccine to 9.94 per 10,000 vaccination events (95% CI: 6.43-14.67) following three or more vaccines. Syncope resulted in injury in about 15% of both vaccine and venipuncture events.

DISCUSSION

Syncope occurs more commonly following venipuncture than vaccination. The number of simultaneously administered vaccines is a risk factor for postvaccination syncope in adolescents.

Adverse events from HPV vaccination in Taiwan

The safety of human papillomavirus (HPV) vaccines has been evaluated continuously in pre-licensure clinical trials, post-marketing surveillance systems, and observational studies. Most studies have found no significant association between serious adverse events and HPV vaccination. However, these studies have focused on Western populations; similar studies focusing on Asian populations are insufficient. Our retrospective cohort study used the HPV-vaccination records of junior high-school adolescent girls aged 12-15 years between 2013 and 2018 in Taiwan's National Immunization Information System and linked them to a registry for beneficiaries in Taiwan's National Health Insurance Database (NHID) to establish the vaccinated group. We selected 19 serious diseases as serious adverse events. We compared the incidence rates of these serious adverse events between the vaccinated group and girls in the same age group population, and we calculated the standardized incidence ratio (SIR) to evaluate the risk of serious adverse events after HPV vaccination. Because of the onset of different types of diseases, we set three periods after the subjects received HPV vaccination: within 3 months, within 1 year, and during the study period (2013-2018). The results showed the incidence rates and the SIRs of 19 selected adverse events. Among the 19 selected serious adverse events, the disease with the highest incidence rate during the study period was fibromyalgia (73.23 cases per million population), and the disease with the lowest incidence rate during the study period was Crohn's disease (0.15 cases per million population). The results showed no statistically significant increases in the risk of 19 selected serious adverse events and indicated no association between HPV vaccination and serious adverse events. Given the benefits and safety of HPV vaccination, our research can reduce concerns about vaccine side effects, inform health policies and improve public and clinician's acceptance of HPV vaccine policy.

Understanding HPV Vaccination Policymaking in Rwanda: A Case of Health Prioritization and Public-Private-Partnership in a Low-Resource Setting

Rwanda is the first African country to implement a national HPV vaccination program in 2011. This study sought to clarify the HPV vaccination policymaking process in Rwanda through the lens of Kingdon's multiple stream framework and Foucault's concept of governmentality. Perspectives of policymakers engaged in HPV vaccination policy were gathered from published sources, along with key informant interviews. Rwanda's track record of successful vaccination programs enabled by a culture of local accountability created public and private sector incentives. Effective stakeholder engagement, health priority setting, and resource mobilization garnered locally and through international development aid, reflect indicators of policy success. The national HPV policymaking process in Rwanda unfolded in a relatively cohesive and stable policy network. Although peripheral stakeholder resistance and a constrained national budget can present a threat to policy survival, the study shows that such factors as the engagement of policy entrepreneurs within a policy network, private sector incentives, and international aid were effective in ensuring policy resolution.

Association between vaccination and the risk of central demyelination: results from a case-referent study

BACKGROUND

Few studies documented the potential association between vaccination and the risk of central demyelination (CD). Specifically, anti-hepatitis B and anti-human papillomavirus (HPV) vaccines have been the subject of distrust with regard to their implication to trigger CD.

METHODS

From a systematic national registry, patients with first signs of CD (cases) were identified and documented for their exposure to vaccination up to 24 months before the first signs occurred. This exposure was compared to that of a representative sample of general practice patients without a history of CD, randomly selected from a national registry (referents). CD cases were 2:1 matched on age, sex, index date (ID), and region of residence. Vaccines against influenza, HPV, hepatitis B and diphtheria-tetanus-pertussis-poliomyelitis-haemophilus (DTPPHae) were considered. Associations between vaccination and CD were assessed using multivariate conditional logistic regressions, controlled for confounding factors.

FINDINGS

564 CD cases were matched to 1,128 randomly selected referents (age range: 2-79 years old). Overall, 123 (22%) CD cases and 320 (28%) referents had received at least one vaccine within 24 months before ID. Adjusted odds ratios (ORs) for any vaccination were 0.69, 95% confidence interval (CI) [0.54-0.88] with respect to any CD first signs, 0.68 [0.51-0.90] for myelitis and 0.70 [0.42-1.17] for optic neuritis. Adjusted ORs for any CD first signs were 1.02 [0.71-1.47] for influenza vaccine (administered in 9.6% of cases and 10.4% of referents) and 0.72 [0.53-0.99] for DTPPHae vaccine (administered in 10.8% of cases and 14.5% of referents). Vaccines against hepatitis B and HPV were only administered in 1.1% and 1.2% of cases and in 2.9% and 3.2% of referents respectively, which statistically explained the point estimates < 1 (ORs of 0.39 [0.16-0.94] and of 0.32 [0.13-0.80]).

INTERPRETATION

No increased risk of CD incidence was observed amongst vaccinated patients. Lower rates of vaccination against hepatitis B and HPV observed in patients with CD compared to referents may be due to the reluctance of physicians to vaccinate patients considered at risk of CD.

Map of thrombogenesis in viral infections and viral-driven tumours

Viruses are pathogenic agents responsible for approximately 10% of all human cancers and significantly contribute to the global cancer burden. Until now, eight viruses have been associated with the development of a broad range of malignancies, including solid and haematological tumours. Besides triggering and promoting oncogenesis, viral infections often go hand-in-hand with haemostatic changes, representing a potential risk factor for venous thromboembolism (VTE). Conversely, VTE is a cardiovascular condition that is particularly common among oncological patients, with a detrimental impact on patient prognosis. Despite an association between viral infections and coagulopathies, it is unclear whether viral-driven tumours have a different incidence and prognosis pattern of thromboembolism compared to non-viral-induced tumours. Thus, this review aims to analyse the existing evidence concerning the association of viruses and viral tumours with the occurrence of VTE. Except for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection, which are associated with a high risk of VTE, little evidence exists concerning the thrombogenic potential associated with oncoviruses. As for tumours that can be induced by oncoviruses, four levels of VTE risk are observed, with hepatocellular carcinoma (HCC) and gastric carcinoma (GC) associated with the highest risk and nasopharyngeal carcinoma (NPC) associated with the lowest risk. Unfortunately, the incidence of cancer-related VTE according to tumour aetiology is unknown. Given the negative impact of VTE in oncological patients, research is required to better understand the mechanisms underlying blood hypercoagulability in viral-driven tumours to improve VTE management and prognosis assessment in patients diagnosed with these tumours.

Extended surveillance to assess safety of 9-valent human papillomavirus vaccine

The safety of 9-valent HPV vaccine (9vHPV) has been established with regard to common and uncommon adverse events. However, investigation of rare and severe adverse events requires extended study periods to capture rare outcomes. This observational cohort study investigated the occurrence of three rare and serious adverse events following 9-valent human papillomavirus (9vHPV) vaccination compared to other vaccinations, in US individuals 9-26 years old, using electronic health record data from the Vaccine Safety Datalink (VSD). We searched for occurrences of Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and stroke following 9vHPV vaccination from October 4, 2015, through January 2, 2021. We compared the risks of GBS, CIDP, and stroke following 9vHPV vaccination to risks of those outcomes following comparator vaccines commonly given to this age group (Td, Tdap, MenACWY, hepatitis A, and varicella vaccines) from January 1, 2007, through January 2, 2021. We observed 1.2 cases of stroke, 0.3 cases of GBS, and 0.1 cases of CIDP per 100,000 doses of 9vHPV vaccine. After observing more than 1.8 million doses of 9vHPV, we identified no statistically significant increase in risks associated with 9vHPV vaccination for any of these adverse events, either combined or stratified by age (9-17 years of age vs. 18-26 years of age) and sex (males vs. females). Our findings provide additional evidence supporting 9vHPV vaccine safety, over longer time frames and for more serious and rare adverse events.

Thrombosis and thromboembolism: Brighton collaboration case definition and guidelines for data collection, analysis, and presentation of immunization safety data

This is a Brighton Collaboration case definition of thrombosis and thromboembolism to be used in the evaluation of adverse events following immunization, and for epidemiologic studies for the assessment of background incidence or hypothesis testing. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of SARS-CoV-2 vaccines. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation. The document underwent peer review by the Brighton Collaboration Network and by selected expert reviewers prior to submission.

Active Postlicensure Safety Surveillance for Recombinant Zoster Vaccine Using Electronic Health Record Data

Recombinant zoster vaccine (RZV) (Shingrix; GlaxoSmithKline, Brentford, United Kingdom) is an adjuvanted glycoprotein vaccine that was licensed in 2017 to prevent herpes zoster (shingles) and its complications in older adults. In this prospective, postlicensure Vaccine Safety Datalink study using electronic health records, we sequentially monitored a real-world population of adults aged ≥50 years who received care in multiple US Vaccine Safety Datalink health systems to identify potentially increased risks of 10 prespecified health outcomes, including stroke, anaphylaxis, and Guillain-Barré syndrome (GBS). Among 647,833 RZV doses administered from January 2018 through December 2019, we did not detect a sustained increased risk of any monitored outcome for RZV recipients relative to either historical (2013-2017) recipients of zoster vaccine live, a live attenuated virus vaccine (Zostavax; Merck & Co., Inc., Kenilworth, New Jersey), or contemporary non-RZV vaccine recipients who had an annual well-person visit during the 2018-2019 study period. We confirmed prelicensure trial findings of increased risks of systemic and local reactions following RZV. Our study provides additional reassurance about the overall safety of RZV. Despite a large sample, uncertainty remains regarding potential associations with GBS due to the limited number of confirmed GBS cases that were observed.

Understanding the public health value and defining preferred product characteristics for therapeutic human papillomavirus (HPV) vaccines: World Health Organization consultations, October 2021-March 2022

The World Health Organization (WHO) global strategy to eliminate cervical cancer (CxCa) could result in >62 million lives saved by 2120 if strategy targets are reached and maintained: 90% of adolescent girls receiving prophylactic human papillomavirus (HPV) vaccine, 70% of women receiving twice-lifetime cervical cancer screening, and 90% of cervical pre-cancer lesions and invasive CxCa treated. However, the cost and complexity of CxCa screening and treatment approaches has hampered scale-up, particularly in low- and middle-income countries (LMICs), and new approaches are needed. Therapeutic HPV vaccines (TxV), which could clear persistent high-risk HPV infection and/or cause regression of pre-cancerous lesions, are in early clinical development and might offer one such approach. During October 2021 to March 2022, WHO, in collaboration with the Bill and Melinda Gates Foundation, convened a series of global expert consultations to lay the groundwork for understanding the potential value of TxV in the context of current CxCa prevention efforts and for defining WHO preferred product characteristics (PPCs) for TxV. WHO PPCs describe preferences for vaccine attributes that would help optimize vaccine value and use in meeting the global public health need. This paper reports on the main discussion points and findings from the expert consultations. Experts identified several ways in which TxV might address challenges in current CxCa prevention programmes, but emphasized that the potential value of TxV will depend on their degree of efficacy and how quickly they can be developed and implemented relative to ongoing scale-up of existing interventions. Consultation participants also discussed potential use-cases for TxV, important PPC considerations (e.g., vaccine indications, target populations, and delivery strategies), and critical modelling needs for predicting TxV impact and cost-effectiveness.

Safety of 4-valent human papillomavirus vaccine in males: a large observational post-marketing study

The 4-valent human papillomavirus (HPV) vaccine (4vHPV vaccine), Gardasil®, is indicated for the prevention of several HPV-related diseases. The objective was to assess the safety of 4vHPV vaccine administered to males as part of routine care. The study used a US health insurance claims database, and included males, age 9 to 26 years, who initiated 4vHPV between October 2009 and December 2016. General safety outcomes were identified using ICD diagnosis codes associated with emergency room visits and hospitalizations in the claims database in risk periods (Days 1–60 and Days 1–14 following vaccine administration) and self-comparison periods (Days 91–150 and 91–104 for the Days 1–60 and Days 1–14 analysis, respectively). Incidence rates (IRs) and relative rates (RRs) with 95% confidence intervals (CIs) were calculated comparing the risk and self-comparison periods. In this study, 114,035 males initiated 4vHPV vaccine and received 202,737 doses. Using the 60-day time window, 5 outcomes had significantly elevated RRs after accounting for multiple comparisons: ear conditions (RR 1.28, 95% CI 1.03–1.59); otitis media and related conditions (RR 1.65, 95% CI 1.09–2.54); cellulitis and abscess of arm (RR 2.17, 95% CI 1.06–4.72); intracranial injury (RR 1.23, 95% CI 1.01–1.50); and concussion (RR 1.29, 95% CI 1.05–1.59). A higher rate of allergic reactions was noted on the day of 4vHPV vaccine receipt compared to other vaccines (21.07 events per 10,000 doses, 95% CI 18.89–23.44 versus 11.44 per 10,000 doses, 95% CI 9.84–13.22). A higher incidence rate of VTE was observed following vaccination but this association was not significant (RR 2.17, 95% CI 0.35–22.74). The 4vHPV vaccine was associated with same-day allergic reactions as well as ear infections, intracranial injury, cellulitis, and concussion within 2 months after vaccination. While allergic reaction and cellulitis are consistent with the known safety profile of 4vHPV vaccine, the association of the other outcomes were determined by an independent Safety Review Committee to be most likely a result of activities common in adolescent males that coincide with the timing of vaccination and not directly related to vaccination itself.

Implications and Contributions: The study results support the general safety of routine immunization with 4vHPV vaccine among males to prevent HPV-related diseases and cancers.

Current Approaches to Vaccine Safety Using Observational Data: A Rationale for the EUMAEUS (Evaluating Use of Methods for Adverse Events Under Surveillance-for Vaccines) Study Design

Post-marketing vaccine safety surveillance aims to detect adverse events following immunization in a population. Whether certain methods of surveillance are more precise and unbiased in generating safety signals is unclear. Here, we synthesized information from existing literature to provide an overview of the strengths, weaknesses, and clinical applications of epidemiologic and analytical methods used in vaccine monitoring, focusing on cohort, case-control and self-controlled designs. These designs are proposed to be evaluated in the EUMAEUS (Evaluating Use of Methods for Adverse Event Under Surveillance-for vaccines) study because of their widespread use and potential utility. Over the past decades, there have been an increasing number of epidemiological study designs used for vaccine safety surveillance. While traditional cohort and case-control study designs remain widely used, newer, novel designs such as the self-controlled case series and self-controlled risk intervals have been developed. Each study design comes with its strengths and limitations, and the most appropriate study design will depend on availability of resources, access to records, number and distribution of cases, and availability of population coverage data. Several assumptions have to be made while using the various study designs, and while the goal is to mitigate any biases, violations of these assumptions are often still present to varying degrees. In our review, we discussed some of the potential biases (i.e., selection bias, misclassification bias and confounding bias), and ways to mitigate them. While the types of epidemiological study designs are well established, a comprehensive comparison of the analytical aspects (including method evaluation and performance metrics) of these study designs are relatively less well studied. We summarized the literature, reporting on two simulation studies, which compared the detection time, empirical power, error rate and risk estimate bias across the above-mentioned study designs. While these simulation studies provided insights on the analytic performance of each of the study designs, its applicability to real-world data remains unclear. To bridge that gap, we provided the rationale of the EUMAEUS study, with a brief description of the study design; and how the use of real-world multi-database networks can provide insights into better methods evaluation and vaccine safety surveillance.

Thrombosis and thrombocytopenia after HPV vaccination

BACKGROUND

Vaccine-induced immune thrombotic thrombocytopenia (VITT) has so far only been reported after adenovirus vector severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines.

OBJECTIVE

We report findings in a 25-year-old woman who presented with thrombocytopenia, venous thrombosis, elevated D-dimer levels, and high levels of platelet-activating antibodies to platelet factor 4-polyanion complexes 10 days after Gardasil 9 vaccination for human papillomavirus (HPV). The patient exhibited clinical and laboratory features in line with the recently defined VITT syndrome, described after adenoviral vector vaccination to prevent coronavirus disease 2019.

CONCLUSION

We report a case of VITT following HPV vaccination. This should raise awareness of the possibility of VITT also occurring after other vaccines, not exclusively adenoviral vector-based SARS-CoV-2 vaccines.

Reduction in Vaccine HPV Type Infections in a Young Women Group (18-25 Years) Five Years after HPV Vaccine Introduction in Colombia

In Colombia, the human papillomavirus (HPV) vaccine was launched in 2012 in the context of a school-based national vaccination program targeting girls ages 9 to 14 and offering catch-up vaccination for girls ages 14 to 17. In this study, we evaluated the program's impact on type-specific HPV infection by comparing HPV cervical prevalence among vaccinated and nonvaccinated women. This is a comparative cross-sectional study conducted 5 years after the quadrivalent HPV vaccination implementation in a sentinel Colombian City. This study included young women (18-25 years old) who had been vaccinated in the catch-up group and were attending universities and technical institutions, and women who attended primary health care facilities for Pap smear screening. The HPV prevalence of 1,287 unvaccinated women was compared with the prevalence of 1,986 vaccinated women. The prevalence of HPV16/18 infections was significantly lower in vaccinated compared with unvaccinated women (6.5% vs. 15.4%; P < 0.001), whereas for HPV6/11 infections, a decrease of 63.7% in vaccinated women (1.02% vs. 2.81%) was observed. The adjusted effectiveness to HPV16/18 was 61.4%; 95% CI, 54.3%-67.6%. However, the effectiveness against HPV16/18 was significantly higher among women vaccinated before their sexual debut 91.5%; 95% CI, 86.8-94.5, compared with effectiveness for vaccination after their sexual debut, 36.2%; 95% CI, 23.6-46.7. Five years after the introduction of HPV vaccines in Colombia, high effectiveness of HPV to prevent HPV16/18 infections is observed in the catch-up cohorts including virgin and sexually active women. PREVENTION RELEVANCE: Monitoring HPV vaccines post-licensure plays an important role in assessing the progress of immunization programs, demonstrating the impact of vaccines on the population, and providing data for policy needs. In Colombia, HPV vaccines showed effectiveness when administered before start of sexual activity, and two doses are sufficient to achieve good protection.

Risk of Guillain-Barré syndrome after vaccination against human papillomavirus: a systematic review and meta-analysis, 1 January 2000 to 4 April 2020

BackgroundGuillain-Barré syndrome (GBS) is a rare autoimmune disease that can follow viral infections and has in a few cases been linked to vaccinations. Pre-licensure clinical trials did not observe an association between human papillomavirus (HPV) vaccination and GBS, a post-marketing study from 2017 reported an increased relative risk.AimWe assessed the risk of GBS after HPV vaccination through a systematic literature review and meta-analysis.MethodsWe searched Embase, MEDLINE and Cochrane for studies reporting on the risk of GBS after HPV vaccination in individuals aged ≥ 9 years, published between 1 January 2000 and 4 April 2020, excluding studies without a comparator group. Seven studies reporting relative effect sizes were pooled using random-effects meta-analysis. We assessed quality of evidence using the GRADE approach. Study protocol was registered (PROSPERO No. #CRD42019123533).ResultsOf 602 identified records, we included 25 studies. Based on over 10 million reports, cases of GBS were rare. In 22 studies no increased risk was observed, while in three studies a signal of increased risk of GBS after HPV vaccination was identified. Meta-analysis yielded a pooled random-effects ratio of 1.21 (95% CI: 0.60-2.43); I2 = 72% (95% CI: 36-88). This translates to a number needed to harm of one million to be vaccinated to generate one GBS case. Quality of evidence was very low.ConclusionsThe absolute and relative risk of GBS after HPV vaccination is very low and lacks statistical significance. This is reassuring for the already implemented vaccination programmes and should be used in respective communication activities.

Human Papillomavirus Vaccine Efficacy and Effectiveness against Cancer

Human papillomavirus (HPV) is the most common sexually transmitted infection, with 15 HPV types related to cervical, anal, oropharyngeal, penile, vulvar, and vaginal cancers. However, cervical cancer remains one of the most common cancers in women, especially in developing countries. Three HPV vaccines have been licensed: bivalent (Cervarix, GSK, Rixensart, Belgium), quadrivalent (Merck, Sharp & Dome (Merck & Co, Whitehouse Station, NJ, USA)), and nonavalent (Merck, Sharp & Dome (Merck & Co, Whitehouse Station, NJ, USA)). The current HPV vaccine recommendations apply to 9 years old and above through the age of 26 years and adults aged 27–45 years who might be at risk of new HPV infection and benefit from vaccination. The primary target population for HPV vaccination recommended by the WHO is girls aged 9–14 years, prior to their becoming sexually active, to undergo a two-dose schedule and girls ≥ 15 years of age, to undergo a three-dose schedule. Safety data for HPV vaccines have indicated that they are safe. The most common adverse side-effect was local symptoms. HPV vaccines are highly immunogenic. The efficacy and effectiveness of vaccines has been remarkably high among young women who were HPV seronegative before vaccination. Vaccine efficacy was lower among women regardless of HPV DNA when vaccinated and among adult women. Comparisons of the efficacy of bivalent, quadrivalent, and nonavalent vaccines against HPV 16/18 showed that they are similar. However, the nonavalent vaccine can provide additional protection against HPV 31/33/45/52/58. In a real-world setting, the notable decrease of HPV 6/11/16/18 among vaccinated women compared with unvaccinated women shows the vaccine to be highly effective. Moreover, the direct effect of the nonavalent vaccine with the cross-protection of bivalent and quadrivalent vaccines results in the reduction of HPV 6/11/16/18/31/33/45/52/58. HPV vaccination has been shown to provide herd protection as well. Two-dose HPV vaccine schedules showed no difference in seroconversion from three-dose schedules. However, the use of a single-dose HPV vaccination schedule remains controversial. For males, the quadrivalent HPV vaccine possibly reduces the incidence of external genital lesions and persistent infection with HPV 6/11/16/18. Evidence regarding the efficacy and risk of HPV vaccination and HIV infection remains limited. HPV vaccination has been shown to be highly effective against oral HPV type 16/18 infection, with a significant percentage of participants developing IgG antibodies in the oral fluid post vaccination. However, the vaccines’ effectiveness in reducing the incidence of and mortality rates from HPV-related head and neck cancers should be observed in the long term. In anal infections and anal intraepithelial neoplasia, the vaccines demonstrate high efficacy. While HPV vaccines are very effective, screening for related cancers, as per guidelines, is still recommended.

Bias, Precision and Timeliness of Historical (Background) Rate Comparison Methods for Vaccine Safety Monitoring: An Empirical Multi-Database Analysis

Using real-world data and past vaccination data, we conducted a large-scale experiment to quantify bias, precision and timeliness of different study designs to estimate historical background (expected) compared to post-vaccination (observed) rates of safety events for several vaccines. We used negative (not causally related) and positive control outcomes. The latter were synthetically generated true safety signals with incident rate ratios ranging from 1.5 to 4. Observed vs. expected analysis using within-database historical background rates is a sensitive but unspecific method for the identification of potential vaccine safety signals. Despite good discrimination, most analyses showed a tendency to overestimate risks, with 20%-100% type 1 error, but low (0% to 20%) type 2 error in the large databases included in our study. Efforts to improve the comparability of background and post-vaccine rates, including age-sex adjustment and anchoring background rates around a visit, reduced type 1 error and improved precision but residual systematic error persisted. Additionally, empirical calibration dramatically reduced type 1 to nominal but came at the cost of increasing type 2 error.

Post-licensure safety monitoring of quadrivalent human papillomavirus vaccine using the national adverse event following immunization surveillance system from Zhejiang province, 2018-2020

OBJECTIVES

To evaluate the reporting rate of adverse events following immunization (AEFI) of the quadrivalent human papillomavirus vaccine (4vHPV) and to compare the reporting rate of AEFI following 4vHPV with those following other vaccines.

METHODS

Review and describe the AEFI reported to national adverse event following immunization surveillance system (NAEFISS) in Zhejiang province from 2018 to 2020. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR‑1.96SE >1 (standard error [SE]) was considered as positive signal.

RESULTS

NAEFISS received 238 reports after receipt of 4vHPV and 899,282 doses of 4vHPV were administered during the study period, with a crude reporting rate of 2.7/10000 doses. Fever/redness/induration (101 reports) was the most common event reported (1.12/10000 doses). Two cases of anaphylactic shock, three cases of Guillain Barre Syndrome and two cases of acute disseminated encephalomyelitis were reported. ROR showed positive signals for seizure (ROR‑1.96SE: 2.1), syncope (ROR‑1.96SE: 1.3), allergic rash (ROR‑1.96SE: 1.6) and headache (ROR‑1.96SE: 2.1).

CONCLUSION

The present analysis did not identify new/unexpected safety concerns. Further epidemiological studies are required to systematically validate the data provided by NAEFISS.

Papillomavirus vaccination and Guillain-Barre Syndrome among girls: A cohort study in Spain

BACKGROUND

Studies of the association of Guillain-Barré Syndrome (GBS) with papillomavirus vaccination (HPVv; scheduled from 2007) have provided contradicting results, probably due to the low frequency of this disease. We aimed at estimating that risk relative to non-vaccination among girls, by using the Spanish Primary Care Database for Pharmacoepidemiological Research (BIFAP).

METHODS

A cohort study of girls aged 9-18 years during 2007-2016 free of GBS or HPVv was selected and followed up to GBS diagnosis. Follow-up time was divided by time-varying HPVv exposure and confounders. Crude Incidence rates (IR per 1,000,000 person-years (py)) and adjusted Hazard Ratios (HR) of GBS were estimated anytime after vaccination compared to non-exposed periods. HRs were also estimated for the first 90 days after HPVv (risk-window) and thereafter.

RESULTS

Out of 388,849 girls, of which 154,255 were vaccinated, 6 'confirmed' GBS cases occurred during non-exposure periods (IR of 5.83 per million person-years; 95% CI: 2.62-12.97) and 3 'confirmed' cases anytime after vaccination (IR of 7.87; 95% CI: 2.54-24.39). The resulting adjusted HR anytime after vaccination was 1.24 (95% CI: 0.19-8.00). All three cases occurred after the risk window of 90 days with an HR of 1.77 (95% CI: 0.25-12.54) for post-exposure periods as compared with non-exposure. Since zero cases occurred during the risk window, no HR could be estimated for exposed periods.

CONCLUSIONS

Incidences of GBS were in line with the range previously reported for young people, supporting the potential of BIFAP for performing studies on GBS. However, a lack of power may be present for quantifying the relative risk of such a rare disease after the vaccination among the study cohort, where we can only exclude an increased risk of 8-times relative to no vaccination.

Safety of vaccines used for routine immunization in the United States: An updated systematic review and meta-analysis

BACKGROUND

Understanding the safety of vaccines is critical to inform decisions about vaccination. Our objective was to conduct a systematic review of the safety of vaccines recommended for children, adults, and pregnant women in the United States.

METHODS

We searched the literature in November 2020 to update a 2014 Agency for Healthcare Research and Quality review by integrating newly available data. Studies of vaccines that used a comparator and reported the presence or absence of key adverse events were eligible. Adhering to Evidence-based Practice Center methodology, we assessed the strength of evidence (SoE) for all evidence statements. The systematic review is registered in PROSPERO (CRD42020180089).

RESULTS

Of 56,603 reviewed citations, 338 studies reported in 518 publications met inclusion criteria. For children, SoE was high for no increased risk of autism following measles, mumps, and rubella (MMR) vaccine. SoE was high for increased risk of febrile seizures with MMR. There was no evidence of increased risk of  intussusception with rotavirus vaccine at the latest follow-up (moderate SoE), nor of diabetes (high SoE). There was no evidence of increased risk or insufficient evidence for key adverse events for newer vaccines such as 9-valent human papillomavirus and meningococcal B vaccines. For adults, there was no evidence of increased risk (varied SoE) or insufficient evidence for key adverse events for the new adjuvanted inactivated influenza vaccine and recombinant adjuvanted zoster vaccine. We found no evidence of increased risk (varied SoE) for key adverse events among pregnant women following tetanus, diphtheria, and acellular pertussis vaccine, including stillbirth (moderate SoE).

CONCLUSIONS

Across a large body of research we found few associations of vaccines and serious key adverse events; however, rare events are challenging to study. Any adverse events should be weighed against the protective benefits that vaccines provide.

Do Vaccines Have a Role as a Cause of Autoimmune Neurological Syndromes?

Vaccines are the most important preventive measure against infectious diseases presently available. Although they have led to the eradication or the elimination of some infectious diseases, concerns about safety are among the main reasons for vaccine hesitancy. In some cases, the biological plausibility of a given damage in association with the temporal association between vaccine administration and disease development makes it difficult to define causality and can justify hesitancy. Only well-conducted epidemiological studies with adequate evaluation of results can clarify whether a true association between vaccines and adverse event development truly exists. Autoimmune neurological syndromes that follow vaccine use are among these. In this narrative review, the potential association between vaccines and the development of these syndromes are discussed. Literature analysis showed that most of the associations between vaccines and nervous system autoimmune syndromes that have been reported as severe adverse events following immunization are no longer evidenced when well-conducted epidemiological studies are carried out. Although the rarity of autoimmune diseases makes it difficult to strictly exclude that, albeit exceptionally, some vaccines may induce an autoimmune neurological disease, no definitive demonstration of a potential role of vaccines in causing autoimmune neurological syndromes is presently available. Consequently, the fear of neurological autoimmune disease cannot limit the use of the most important preventive measure presently available against infectious diseases.

Adverse events following HPV vaccination: 11 years of surveillance in Australia

BACKGROUND

Australia was the first country to implement a fully funded vaccination program with quadrivalent human papillomavirus vaccine (4vHPV) in 2007, including males from 2013. We examined adverse events (AE) following vaccination with 4vHPV from 11 years of post-marketing data, focusing on a period of enhanced surveillance and adverse events of special interest (AESI).

METHODS

AE following 4vHPV doses administered between April 2007 and December 2017 reported to Australia's national regulator, the Therapeutic Goods Administration, were examined; reports collected during enhanced surveillance in 2013 and 2014 were analyzed separately. Age and sex-specific rates, using denominator data from the national HPV vaccination register, were determined. Pre-specified AESI were identified using Medical Dictionary for Regulatory Activities (MedDRA®) Preferred Terms and examined in detail.

FINDINGS

Following nine million doses of 4vHPV vaccine administered in Australia, 4551 AE reports were identified. The crude reporting rate was 39.8 per 100 000 doses in the funded cohorts, excluding the enhanced surveillance period. The reported rate of syncope in 12 to 13-year-old males and females was 29.6 per 100 000 doses during enhanced surveillance and 7.1 per 100 000 doses during the remaining study period; rates of syncope were higher in younger compared to older adolescents. The rate of anaphylaxis (0.32 per 100 000 doses) was consistent with published rates. Other AESI including autoimmune disease, postural orthostatic tachycardia syndrome, primary ovarian insufficiency, Guillain-Barré syndrome, complex regional pain syndrome and venous thromboembolism, were reported at low rates and analysis did not reveal unexpected patterns that would suggest causal association.

INTERPRETATION

AESI, apart from syncope, were reported rarely. The higher rate of syncope among younger adolescents highlights the need for management protocols to prevent syncope-related injury. Analysis of this large, longitudinal dataset in a country with high vaccine uptake, including a period of enhanced surveillance, affirms the safety profile of 4vHPV.

Human Papillomavirus Vaccines: An Updated Review

Human papillomavirus (HPV) vaccines, which were introduced in many countries in the past decade, have shown promising results in decreasing HPV infection and related diseases, such as warts and precancerous lesions. In this review, we present the updated information about current HPV vaccines, focusing on vaccine coverage and efficacy. In addition, pan-gender vaccination and current clinical trials are also discussed. Currently, more efforts should be put into increasing the vaccine’s coverage, especially in low- and middle-income countries. Provision of education on HPV and vaccination is one of the most important methods to achieve this. Vaccines that target HPV types not included in current vaccines are the next stage in vaccine development. In the future, all HPV-related cancers, such as head and neck cancer, and anal cancer, should be tracked and evaluated, especially in countries that have introduced pan-gender vaccination programs. Therapeutic vaccines, in combination with other cancer treatments, should continue to be investigated.

Human papillomavirus genotyping on Reunion Island: A cross-sectional study of stored tissue samples

OBJECTIVE

We aim to illustrate and evaluate the prevalence and distribution pattern of cervical human papilloma virus (HPV) genotypes on La Réunion Island, a French overseas territory, with the aim to guide future vaccination policies.

STUDY DESIGN

Between January 2008 and July 2012, files of women undergoing gynaecological examination were retrospectively evaluated at the University Hospital, Reunion Island. Inclusion criteria required cervical biopsies with histopathological diagnosis of high-grade lesions or cancer and ASCUS Pap Smears (atypical squamous cells undetermined significance) results. The INNO-LIPA HPV Genotyping Extra® test was used for HPV genotyping.

RESULTS

A total of 401 ASCUS Pap Smears and 94 cervical biopsies were analyzed, of which 162 smears and 63 biopsies were HPV DNA positive (40.4 % and 67 % respectively). Detailed breakdowns of HPV genotype-specific distribution reported prevalence of HPV 16, 31, 33, 51 and 52. Of the 63 HPV-positive biopsies, 61 (96.8 %) contained at least one HPV genotype that is contained in the 9-valent HPV vaccine. The incremental preventable fraction of HPV infections that could have been added by the new 9-valent vaccine to the current bivalent vaccine was estimated at 26.2 %.

CONCLUSIONS

Immunization with 9-valent vaccine should be effective, and in the long term, may reduce cervical cancer incidence in Reunion Island. Nevertheless, vaccination rates and coverage need to be maintained and improved.

An educational intervention to improve attitudes regarding HPV vaccination and comfort with counseling among US medical students

Many medical students are not comfortable recommending the human papillomavirus (HPV) vaccine because they do not feel prepared to discuss it with their patients. A prior study demonstrated that this is particularly a problem among unvaccinated students. Our purpose was to determine if medical student attitudes and comfort with counseling could be improved by attending a single lecture delivered by an expert on the topic. To assess the effects of the educational program, we conducted pre- and posttests on medical students before and after a single lecture on HPV vaccination. Changes in items related to attitude and comfort were examined. Student characteristics associated with changes in scores were also examined and compared. A total of 256 medical students participated in the pre- and posttests. Before the lecture, students demonstrated low knowledge of HPV vaccination and did not feel comfortable counseling parents of younger patients. However, students <30 years of age demonstrated significant improvements after the lecture in comfort. Asian and Hispanic students showed the greatest improvement in comfort with counseling, as did students who reported they had not received the HPV vaccine. Attending a single lecture given by an expert can improve medical students' attitudes and comfort with HPV vaccine counseling, especially if the students were not vaccinated themselves. This study suggests that including material on HPV vaccination in the standard medical student curriculum could help increase physician recommendation for the HPV vaccine.

A Bayesian approach to sequential analysis in post-licensure vaccine safety surveillance

With rapid development of computing technology, Bayesian statistics have increasingly gained more attention in various areas of public health. However, the full potential of Bayesian sequential methods applied to vaccine safety surveillance has not yet been realized, despite acknowledged practical benefits and philosophical advantages of Bayesian statistics. In this paper, we describe how sequential analysis can be performed in a Bayesian paradigm in the field of vaccine safety. We compared the performance of the frequentist sequential method, specifically, Maximized Sequential Probability Ratio Test (MaxSPRT), and a Bayesian sequential method using simulations and a real world vaccine safety example. The performance is evaluated using three metrics: false positive rate, false negative rate, and average earliest time to signal. Depending on the background rate of adverse events, the Bayesian sequential method could significantly improve the false negative rate and decrease the earliest time to signal. We consider the proposed Bayesian sequential approach to be a promising alternative for vaccine safety surveillance.

Primary ovarian insufficiency and human papilloma virus vaccines: a review of the current evidence

Human papilloma virus is the primary causative agent for cervical cancer, and vaccination is the primary means of preventing anogenital cancers caused by human papilloma virus infection. Despite the availability of human papilloma virus vaccines for more than a decade, coverage rates lag behind those for other vaccines. Public concerns regarding safety of human papilloma virus vaccines have been identified as an important barrier to vaccination, including concerns that the human papilloma virus vaccine may cause primary ovarian insufficiency, driven in part by isolated reports of ovarian failure following the human papilloma virus vaccine. We summarize published peer-reviewed literature on human papilloma virus vaccines and primary ovarian insufficiency, reviewing information contained in the case reports and series. Healthcare providers should address any patient concerns about primary ovarian insufficiency and the human papilloma virus vaccine by acknowledging the case reports but noting the lack of association found in a recently published epidemiologic study of approximately 60,000 female individuals. Current evidence is insufficient to suggest or to support a causal relationship between human papilloma virus vaccination and primary ovarian insufficiency.

Safety of the 9-Valent Human Papillomavirus Vaccine

BACKGROUND

The 9-valent human papillomavirus vaccine (9vHPV) was approved for females and males aged 9 to 26 years in 2014. We analyzed postlicensure surveillance reports to the Vaccine Adverse Event Reporting System (VAERS).

METHODS

We searched VAERS data for US reports of adverse events (AEs) after 9vHPV from December 2014 through December 2017. We calculated reporting rates and conducted empirical Bayesian data mining to identify disproportional reporting. Physicians reviewed reports for selected prespecified conditions.

RESULTS

VAERS received 7244 reports after 9vHPV: 31.2% among females, 21.6% among males, and for 47.2%, sex was not reported. Overall, 97.4% of reports were nonserious. Dizziness, syncope, headache, and injection site reactions were most commonly reported; the most commonly reported AEs were similar between females and males. Two reports of death after 9vHPV were verified; no information in autopsy reports or death certificates suggested a causal relationship with vaccination. Approximately 28 million 9vHPV doses were distributed during the study period; crude AE reporting rates were 259 reports per million 9vHPV doses distributed for all reports and 7 per million doses distributed for serious reports. Syncope (a known AE associated with human papillomavirus vaccination) and several types of vaccine administration errors (eg, administered at wrong age) exceeded the statistical threshold for empirical Bayesian data mining findings.

CONCLUSIONS

No new or unexpected safety concerns or reporting patterns of 9vHPV with clinically important AEs were detected. The safety profile of 9vHPV is consistent with data from prelicensure trials and from postmarketing safety data of its predecessor, the quadrivalent human papillomavirus vaccine.

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.

Vaccine safety in infants and children

Immunization is crucial to maintaining public health. This article addresses the benefits of childhood vaccinations and educates parents on the myths surrounding possible adverse reactions.

Investigating safety profiles of human papillomavirus vaccine across group differences using VAERS data and MedDRA

Background

The safety of vaccines is a critical factor in maintaining public trust in national vaccination programs. This study aimed to evaluate the safety profiles of human papillomavirus (HPV) vaccines with regard to the distribution of adverse events (AE) across gender and age, and the correlations across various AEs using the Food and Drug Administration/Centers for Disease Control and Prevention Vaccine Adverse Event Reporting System (VAERS).

Methods

For analyses, 27,348 patients aged between 9 and 25 years old with at least one AE reported in VAERS between the year of 2006 and 2017 were included. AEs were summarized into two levels: the lower level preferred term (PT) and higher level system organ classes (SOCs) based on the structure of Medical Dictionary for Regulatory Activities (MedDRA). A series of statistical analyses were applied on both levels of AEs. Zero-truncated Poisson regression and multivariate logistic regression models were first developed to assess the rate and risk of SOCs across age groups and genders. Pairwise Pearson correlation analyses and hierarchical clustering analyses were then conducted to explore the interrelationships and clustering pattern among AEs.

Results

We identified 27,337 unique HPV vaccine reports between 2006 and 2017. Disproportional reporting of AEs was observed across age and gender in 21 SOCs (p < 0.05). The correlation analyses found most SOCs demonstrate weak positive correlations except for five pairs which were negatively correlated: skin and subcutaneous tissue disorders + injury poisoning and procedural complications; skin and subcutaneous tissue disorders + nervous system disorders; Skin and subcutaneous tissue disorders + pregnancy, puerperium and perinatal conditions; nervous system disorders + pregnancy, puerperium and perinatal conditions; pregnancy, puerperium and perinatal conditions + general disorders and administration site conditions. Nervous system disorders had the most AEs which contributed to 12,448 (46%) cases. In the further analyses of correlations between PT in nervous system disorders, the three most strongly correlated AEs were psychiatric disorders (r = 0.35), gastrointestinal disorders (r = 0.215), and musculoskeletal and connective tissue disorders (r = 0.261). We observed an inter-SOCs correlation of the PTs among AE pairs by nervous system disorders/psychiatric disorders/gastrointestinal disorders/musculoskeletal and connective tissue disorders.

Conclusions

The analyses revealed a different distribution pattern of AEs across gender and age subgroups in 21 SOC level AEs. Correlation analyses and hierarchical clustering analyses further revealed several correlated patterns across various AEs. However, findings from this study should be interpreted with caution. Further clinical studies are needed to understand the heterogeneity of AEs reporting across subgroups and the biological pathways among the statistically correlated AEs.

Clinical Controversies in Cervical Cancer Screening

Through the implementation of systematic cervical cancer screening in the mid-20th century, the United States and other developed countries have seen death rates from cervical cancer decreased by ≥70%.The purpose of this article is to address several of the most controversial issues associated with cervical cancer screening recommendations in light of historical and evolving data. In this article, we will explore the controversies around the age at which to initiate and exit screening, human papilloma virus testing alone as a primary screening approach, and the impact of human papilloma virus vaccination on cervical cancer rates.

Use of routinely collected electronic healthcare data for postlicensure vaccine safety signal detection: a systematic review

Background

Concerns regarding adverse events following vaccination (AEFIs) are a key challenge for public confidence in vaccination. Robust postlicensure vaccine safety monitoring remains critical to detect adverse events, including those not identified in prelicensure studies, and to ensure public safety and public confidence in vaccination. We summarise the literature examined AEFI signal detection using electronic healthcare data, regarding data sources, methodological approach and statistical analysis techniques used.

Methods

We performed a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Five databases (PubMed/Medline, EMBASE, CINAHL, the Cochrane Library and Web of Science) were searched for studies on AEFIs monitoring published up to 25 September 2017. Studies were appraised for methodological quality, and results were synthesised narratively.

Result

We included 47 articles describing AEFI signal detection using electronic healthcare data. All studies involved linked diagnostic healthcare data, from the emergency department, inpatient and outpatient setting and immunisation records. Statistical analysis methodologies used included non-sequential analysis in 33 studies, group sequential analysis in two studies and 12 studies used continuous sequential analysis. Partially elapsed risk window and data accrual lags were the most cited barriers to monitor AEFIs in near real-time.

Conclusion

Routinely collected electronic healthcare data are increasingly used to detect AEFI signals in near real-time. Further research is required to check the utility of non-coded complaints and encounters, such as telephone medical helpline calls, to enhance AEFI signal detection.

Trial registration number

CRD42017072741.

HPV Vaccination in Latin America: Global Challenges and Feasible Solutions

HPV vaccine programs in Latin America run the risk of repeating the problems associated with Papanicolaou (Pap) test programs, an efficient, life-saving tool that is unfortunately underutilized for cancer prevention, in low- and middle-income countries. There is a great need for vigilance in the ongoing implementation of the HPV vaccine in Latin America.

Long term risk of developing type 1 diabetes after HPV vaccination in males and females

INTRODUCTION

Despite minimal evidence, public concerns that the human papillomavirus (HPV) vaccine can cause autoimmune diseases (AD) persist. We evaluated whether HPV vaccine is associated with a long-term increased risk of diabetes mellitus type 1 (DM1).

METHODS

This was a retrospective cohort study in which we identified all potential DM1 cases from Kaiser Permanente Northern California (KPNC) members who were between 11 and 26 years old any time after June 2006 through December 2015. We chart reviewed a random sample of 100 DM1 cases to confirm diagnosis and to develop a computer algorithm that reliably determined symptom onset date. Our DM1 Analysis Population comprised all individuals who met membership criteria and who were age and sex eligible to have received HPV vaccine. We adjusted for age, sex, race, Medicaid, and years of prior KPNC membership by stratification using a Cox multiplicative hazards model with a calendar timeline.

RESULTS

Our DM1 analysis included 911,648 individuals. Of 2613 DM1 cases identified, 338 remained in the analysis after applying our algorithm, HPV vaccine eligibility and membership criteria. Over the 10 years of the study period, comparing vaccinated with unvaccinated persons, we did not find an increased risk of DM1 associated with HPV vaccine receipt (hazard ratio 1.21, 95% Confidence Interval 0.94, 1.57).

CONCLUSIONS

We found no increased risk for development of DM1 following HPV vaccination. Our study provides reassurance that during the 10-year time period after HPV vaccine was introduced, there was no substantial increased risk for DM1 following HPV vaccination.

Addressing HPV vaccine myths: practical information for healthcare providers

Human papillomavirus (HPV) vaccine uptake consistently lags behind that of other adolescent vaccines. In 2017, uptake of a single HPV vaccine dose and HPV vaccine series completion was 66% and 49%, respectively, compared to uptake of tetanus, diphtheria, and acellular pertussis vaccine (89%) and quadrivalent meningococcal conjugate vaccine (85%). Reasons for not vaccinating adolescents again HPV are varied, and in many cases, are rooted in commonly spread myths and misperceptions about the vaccine. In this review, we address five key myths - HPV vaccination is not effective at preventing cancer; Pap smears are sufficient to prevent cervical cancer; HPV vaccination is not safe; HPV vaccination is not needed since most infections are naturally cleared by the immune system; 11-12 years of age is too young to vaccinate. For each myth, we summarize the scientific evidence refuting the myth and provide speaking prompts for healthcare professionals to communicate about HPV vaccination.

Development of an Intervention to Reduce Pain and Prevent Syncope Related to Adolescent Vaccination

INTRODUCTION

There is a lack of research into the perspectives of patients, parents, and clinicians regarding strategies for vaccine-related pain and syncope prevention that may improve the adolescent vaccination experience and encourage future vaccination.

OBJECTIVE

To develop an intervention on the basis of preference for strategies to reduce pain and prevent syncope associated with adolescent vaccination.

METHODS

We conducted focus groups and interviews with 8 recently vaccinated Kaiser Permanente Northwest (KPNW) members aged 11 to 17 years and their parents to explore perceptions of pain and syncope after vaccination as well as receptivity to potential interventions. Additionally, we interviewed 7 clinical staff who routinely vaccinate children. We conducted content analysis to identify promising interventions and conducted a data synthesis workshop to select a final intervention for piloting.

RESULTS

All participants expressed willingness to use previsit education, breathing exercises, social support or distraction, and water consumption. Patients and parents expressed a need for verbal education and messaging about potential vaccine-related outcomes, and clinicians noted a need to identify patients who are anxious before a vaccination visit. Most participants suggested a "comfort menu" intervention, to include comfort and distraction items that medical staff offer adolescents before and during vaccination.

CONCLUSION

Patients, parents, and clinicians acknowledged the value of interventions to reduce pain and syncope after adolescent vaccination. Stakeholders identified a comfort menu as the intervention to be piloted at 2 KPNW pediatric clinics. Further research is needed to test the effectiveness of the "Vaccination Comfort Menu" intervention in improving vaccination experiences and continued receipt of vaccinations.

Vaccination against HPV virus: a systematic review of economic evaluation studies for developed countries

INTRODUCTION

During the last years, a significant number economic evaluations of HPV vaccination has been published. Given that cost-effectiveness constitutes an essential part of decision-making with regards to the reimbursement of a health technology, the purpose of this study is to provide a supportive tool to decision-makers regarding the economic efficiency of the introduction of HPV vaccination to national immunization programs.

AREAS COVERED

The PubMed database was searched in order to identify cost-effectiveness studies for HPV vaccination. A total of 42 articles were finally retrieved. All retrieved cost-effectiveness ratios (ICERs) were converted in the same currency unit (I$) and then inflated to the same year (2015) in order to facilitate cross-country comparisons.

RESULTS

Overall, vaccination against HPV 6,11,16,18 types appears to have a ICER with mean value of I$25132/QALY, whereas the mean ICER of vaccination against oncogenic HPV 16,18 types is estimated at I$38,253/QALY.

EXPERT COMMENTARY

HPV vaccination would be a cost-effective intervention in the setting of high-income countries and could reduce the incidence of HPV-related diseases.

Safety of Human Papillomavirus Vaccines: An Updated Review

Human papillomavirus (HPV) vaccines are now included in immunisation programmes in 71 countries. Unfortunately, uptake has been impacted in some countries by reduced confidence in the safety of the HPV vaccine. In 2013, we published an extensive review demonstrating a reassuring safety profile for bivalent (2vHPV) and quadrivalent (4vHPV) vaccines. A nonavalent (9vHPV) vaccine is now available and HPV immunisation programmes have been extended to males in 11 countries. The aim of this updated narrative review was to examine the evidence on HPV vaccine safety, focusing on the 9vHPV vaccine, special populations and adverse events of special interest (AESI). The previous searches were replicated to identify studies to August 2016, including additional search terms for AESI. We identified 109 studies, including 15 population-based studies in over 2.5 million vaccinated individuals across six countries. All vaccines demonstrated an acceptable safety profile; injection-site reactions were slightly more common for 9vHPV vaccine than for 4vHPV vaccine. There was no consistent evidence of an increased risk of any AESI, including demyelinating syndromes or neurological conditions such as complex regional pain or postural orthostatic tachycardia syndromes. The risk-benefit profile for HPV vaccines remains highly favourable.

Vaccine-preventable diseases, vaccines and Guillain-Barre' syndrome

Guillain-Barré syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy. Infections and vaccines have been hypothesized to play a role in triggering GBS development. These beliefs can play a role in reducing vaccination coverage. In this report, data concerning this hypothesis are discussed. It is shown that an association between vaccine administration and GBS has never been proven for most of debated vaccines, although it cannot be definitively excluded. The only exception is the influenza vaccine, at least for the preparation used in 1976. For some vaccines, such as measles/mumps/rubella, human papillomavirus, tetravalent conjugated meningococcal vaccine, and influenza, the debate between supporters and opponents of vaccination remains robust and perception of vaccines' low safety remains a barrier to achieving adequate vaccination coverage. Less than 1 case of GBS per million immunized persons might occur for these vaccines. However, in some casesimmunization actually reduces the risk of GBS development. In addition, the benefits of vaccination are clearly demonstrated by the eradication or enormous decline in the incidence of many vaccine-preventable diseases. These data highlight that the hypothesized risks of adverse events, such as GBS, cannot be considered a valid reason to avoid the administration of currently recommended vaccines.

Recommendations for cervical cancer prevention and control in Ghana: public education and human papillomavirus vaccination

Globally, cervical cancer is a major public health issue causing increasing morbidity and mortality especially in low- and middle-income countries where preventive and control measures are lacking. In Ghana, it is the most common cancer among women. Approaches to reduce the incidence and mortality of the disease in Ghana have had little success due to lack of accurate data on the disease among other factors, to inform policies on prevention, early detection, diagnosis and treatment. Additionally, the lack of clear commitment, policy direction and resources has hindered the scale-up of some of the initiatives implemented to curb the cervical cancer situation in Ghana. In this paper, we make recommendations on cervical cancer education and human papillomavirus vaccination. A collaborative approach is needed involving both private and government organizations, health professionals and the general public. Public education on cervical cancer and HPV vaccination needs to be delivered through a mixture of systems including both healthcare facilities and outreach programs, involving teachers, youth groups, community members and professional bodies. The vaccination of adolescents aged 10-14 years using the nonavalent HPV vaccine will be important in reducing the incidence and mortality of cervical cancer in Ghana. The integration of public education on cervical cancer prevention, HPV vaccination and screening programs into both medical and public health services is critical in achieving high coverage of these programs.

FUNDING

None.

Feasibility of a pilot intervention to reduce pain and syncope during adolescent vaccination

PURPOSE

Vaccines recommended for adolescents are considered safe and effective, however administration may occasionally result in acute pain at the injection site or syncope (fainting). These adverse effects pose a risk to patient safety and are potential barriers to adherence to future vaccinations. We assessed a novel intervention designed to help prevent acute pain and syncope associated with adolescent vaccinations.

METHODS

We conducted a 3-month pilot study to assess the feasibility and acceptability of a vaccination comfort menu within two Kaiser Permanente Northwest pediatric clinics. The menu offered a variety of comfort items (e.g., cold packs, squeeze balls) that children could select prior to their vaccination. We surveyed parents of recently vaccinated adolescents and interviewed providers to assess the implementation and effectiveness of the intervention.

RESULTS

Response rate for the parent survey was 33% (378/1136). Only 20% of the parents reported that their provider offered the comfort menu during the vaccination visit. Approximately 50% of the adolescents who were offered the menu selected a comfort item and most of these participants reported that the item was very (35%) or somewhat (38%) helpful in improving their vaccination experience. Per provider interviews, common barriers to implementing the intervention included lack of time and convenience, and the brevity of the pilot period.

CONCLUSIONS

The comfort menu may improve the vaccination experience of youth and increase the likelihood of adherence with future vaccinations. However, only 20% of the parents reported that their provider offered the menu during the vaccination visit. Additional research is needed to determine the feasibility of implementing this intervention on a larger scale, as well as assessing whether the intervention has a significant impact on reducing adverse events.

Human papillomavirus vaccine and demyelinating diseases-A systematic review and meta-analysis

Approved in 2006, human papillomavirus (HPV) vaccines were initially targeted for girls aged 9-14 years. Although the safety of these vaccines has been monitored through post-licensure surveillance programmes, cases of neurological events have been reported worldwide. The present study aimed to assess the risk of developing demyelination after HPV immunization by meta-analysing risk estimates from pharmacoepidemiologic studies. A systematic review was conducted in Medline, Embase, ISI Web of Science and the Cochrane Library from inception to 10 May 2017, without language restriction. Only observational studies including a control group were retained. Study selection was performed by two independent reviewers with disagreements solved through discussion. This meta-analysis was performed using a generic inverse variance random-effect model. Outcomes of interest included a broad category of central demyelination, multiple sclerosis (MS), optic neuritis (ON), and Guillain-Barré syndrome (GBS), each being considered independently. Heterogeneity was investigated; sensitivity and subgroup analyses were performed when necessary. In parallel, post-licensure safety studies were considered for a qualitative review. This study followed the PRISMA statement and the MOOSE reporting guideline. Of the 2,863 references identified, 11 articles were selected for meta-analysis. No significant association emerged between HPV vaccination and central demyelination, the pooled odds ratio being 0.96 [95% CI 0.77-1.20], with a moderate but non-significant heterogeneity (I² = 29%). Similar results were found for MS and ON. Sensitivity analyses did not alter our conclusions. Findings from qualitative review of 14 safety studies concluded in an absence of a relevant signal. Owing to limited data on GBS, no meta-analysis was performed for this outcome. This study strongly supports the absence of association between HPV vaccines and central demyelination.

Post-licensure safety monitoring of quadrivalent human papillomavirus vaccine in the Vaccine Adverse Event Reporting System (VAERS), 2009-2015

BACKGROUND

The Food and Drug Administration (FDA) approved quadrivalent human papillomavirus vaccine (4vHPV) for use in females and males aged 9-26 years, since 2006 and 2009 respectively. We characterized reports to the Vaccine Adverse Event Reporting System (VAERS), a US spontaneous reporting system, in females and males who received 4vHPV vaccination.

METHODS

We searched VAERS for US reports of adverse events (AEs) following 4vHPV from January 2009 through December 2015. Signs and symptoms were coded using Medical Dictionary for Regulatory Activities (MedDRA). We calculated reporting rates and conducted empirical Bayesian data mining to identify disproportional reports. Clinicians reviewed available information, including medical records, and reports of selected pre-specified conditions.

FINDINGS

VAERS received 19,760 reports following 4vHPV; 60.2% in females, 17.2% in males, and in 22.6% sex was missing. Overall, 94.2% of reports were non-serious; dizziness, syncope and injection site reactions were commonly reported in both males and females. Headache, fatigue and nausea were commonly reported serious AEs. More than 60 million 4vHPV doses were distributed during the study period. Crude AE reporting rates were 327 reports per million 4vHPV doses distributed for all reports, and 19 per million for serious reports. Among 29 verified reports of death, there was no pattern of clustering of deaths by diagnosis, co-morbidities, age, or interval from vaccination to death.

INTERPRETATION

No new or unexpected safety concerns or reporting patterns of 4vHPV with clinically important AEs were detected. Safety profile of 4vHPV is consistent with data from pre-licensure trials and postmarketing safety data.

What information can change the attitude of teachers toward the human papillomavirus vaccine?

AIM

We conducted a self-administered survey on the perception of teachers toward human papillomavirus (HPV) vaccine to determine the ways to increase their willingness to encourage its use.

METHODS

Answers were obtained both prior to and after having the teachers read five brief information articles: (i) cervical cancer knowledge, (ii) vaccine knowledge, (iii) result of a survey in Nagoya, (iv) news report of the World Health Organization statement and (v) articles written by Dr Muranaka, a journalist.

RESULTS

Most of the respondents (180/247) did not know about the natural history of cervical cancer. Only 36% knew that HPV is the cause of cervical cancer, although 63% knew that HPV vaccine would prevent cervical cancer. Few respondents had knowledge regarding adverse events following immunization and the survey results from Nagoya. Among those who were initially negative for the HPV vaccine, only 43% revealed that they fully understood its safety and only 29% reversed their opinion to recommend vaccination to their daughters and/or students, even after reading our informational material. The most useful information for changing their attitudes was to increase their understanding of vaccines and informing them about Nagoya city survey results. They mostly wanted a proof of the preventive effects of the vaccine on cervical cancer in Japan.

CONCLUSION

Gynecologists and pediatricians must proactively communicate accurate scientific information to the government and the media to spread awareness among people in Japan. Also, we must try to demonstrate the capabilities of this vaccine to prevent cervical cancer and/or its precancerous lesions.