The Basics of Epidemiology

Epidemiology contributes to vaccine development and delivery by estimating disease burdens, identifying target populations for immunization, designing clinical trials to show vaccine-induced benefits and risks, and for formulating immunization policy. To estimate disease burden, a case definition is needed first. This may have several sets of criteria, depending on how definite the diagnosis is to be. Epidemiological studies to determine time, place, and person are referred to as descriptive epidemiology. Epidemiological studies to determine causes and effects are referred to as analytical epidemiology. Epidemiological studies may potentially be biased (systemic errors). Bias must be distinguished from confounding (interfering factors that are linked with both, exposure and outcome). Vaccine efficacy studies assess causality between vaccination and disease reduction in a prospective cohort design. Participants are assigned to receive vaccine or placebo usually in a double-blind, randomized fashion and efficacy is calculated from incidence reduction during the study period. Impact studies are observational studies and encompass e.g., describing disease reduction in a population over time after introduction of a vaccine, as well as cohort studies where vaccine effectiveness is calculated from cohorts in which vaccine administration is only observed. Observational studies are timesaving and less costly compared with prospective cohort studies. However, they are prone to various types of bias, e.g. recall bias if exposure status and outcome status are based on the participant's memory.

Evidence of disorientation towards immunization on online social media after contrasting political communication on vaccines. Results from an analysis of Twitter data in Italy

Background In Italy, in recent years, vaccination coverage for key immunizations as MMR has been declining to worryingly low levels, with large measles outbreaks. As a response in 2017, the Italian government expanded the number of mandatory immunizations introducing penalties to unvaccinated children’s families. During the 2018 general elections campaign, immunization policy entered the political debate with the government in-charge blaming oppositions for fuelling vaccine scepticism. A new government (formerly in the opposition) established in 2018 temporarily relaxed penalties and announced the introduction of forms of flexibility. Objectives and methods First, we supplied a definition of disorientation, as the “lack of well-established and resilient opinions among individuals, therefore causing them to change their positions as a consequence of sufficient external perturbations”. Second, procedures for testing for the presence of both short and longer-term collective disorientation in Twitter signals were proposed. Third, a sentiment analysis on tweets posted in Italian during 2018 on immunization topics, and related polarity evaluations, were used to investigate whether the contrasting announcements at the highest political level might have originated disorientation amongst the Italian public. Results Vaccine-relevant tweeters’ interactions peaked in response to main political events. Out of retained tweets, 70.0% resulted favourable to vaccination, 16.4% unfavourable, and 13.6% undecided, respectively. The smoothed time series of polarity proportions exhibit frequent large changes in the favourable proportion, superimposed to a clear up-and-down trend synchronized with the switch between governments in Spring 2018, suggesting evidence of disorientation among the public. Conclusions The reported evidence of disorientation for opinions expressed in online social media shows that critical health topics, such as vaccination, should never be used to achieve political consensus. This is worsened by the lack of a strong Italian institutional presence on Twitter, calling for efforts to contrast misinformation and the ensuing spread of hesitancy. It remains to be seen how this disorientation will impact future parents’ vaccination decisions.

Reduced neutralization of SARS-CoV-2 B.1.617 variant by inactivated and RBD-subunit vaccine

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Spike protein that mediates coronavirus entry into host cells is a major target for COVID-19 vaccines and antibody therapeutics. However, multiple variants of SARS-CoV-2 have emerged, which may potentially compromise vaccine effectiveness. Using a pseudovirus-based assay, we evaluated SARS-CoV-2 cell entry mediated by the viral Spike B.1.617 and B.1.1.7 variants. We also compared the neutralization ability of monoclonal antibodies from convalescent sera and neutralizing antibodies (NAbs) elicited by CoronaVac (inactivated vaccine) and ZF2001 (RBD-subunit vaccine) against B.1.617 and B.1.1.7 variants. Our results showed that, compared to D614G and B.1.1.7 variants, B.1.617 shows enhanced viral entry and membrane fusion, as well as more resistant to antibody neutralization. These findings have important implications for understanding viral infectivity and for immunization policy against SARS-CoV-2 variants.

Understanding Parents’ Views Toward the Newly Enacted HPV Vaccine School Entry: A Qualitative Study

Background: Human papillomavirus vaccine (HPV) is an important tool for prevention of HPV- related cancers. In Puerto Rico, the Secretary of Health established a school entry requirement of at least 1 dose of HPV vaccination in girls and boys aged 11 and 12 years taking effect in August 2018. Our study aims to examine parents’ views and opinions of the process of implementing the new HPV vaccination school entry policy in Puerto Rico, and understand barriers and facilitators related to this HPV immunization policy. Methods: Three focus group (n=12) and eight in-depth semi-structured interviews were performed, along with a survey. The interviews were recorded and transcript by our staff members. Through a thematic analysis were identified emergent themes. Results: Lack of information in relation to the policy were the theme most mentioned in the interviews. Moreover, participants expressed that previous negative experiences, from friends or family member, adverse effect and the lack of communication from school and healthcare providers deter them from the decision of vaccinated their kids. Barriers in the process of soliciting an exemption was discussed. Conclusion: Most barriers mentioned by participants who express hesitation about vaccinating their kids with the HPV vaccine, are modifiable providing parents information about the mandate’s implementation, and educational materials that address their concerns related to the vaccine’s side effects. Implementation of this efforts, however, need to consider impacting the school (teachers, principal directors, and administrative staff), the government and parents. This multilevel approach will help to improve the dissemination of information about HPV vaccination in order to clarify doubts and misinformation among hesitant parents.

National Immunization Technical Advisory Groups (NITAGs): A schema for evaluating and comparing foundation instruments and NITAG operations

The individual and community health benefits of vaccination have received significant attention and are now well understood. However, much less is known about immunization as a regulated space, its principles and standards and its institutions and instruments. In 2011, the World Health Organization (WHO) recommended that National Immunization Technical Advisory Groups (NITAGs) be established in each member country. NITAGSs are envisioned as independent, multidisciplinary expert groups within the national immunization framework, tasked with providing evidence-based evaluations and recommendations to governmental decision-makers about specific vaccines, vaccine-dosing, vaccine program development and immunization policy and practice more generally. As of 2020, 171 WHO countries have formed NITAGs. The widespread formation of NITAGs has highlighted an absence of sustained scholarship around immunization as a policy area subject to law, and it has given rise to many governance and operational questions. In 2017, for example, representatives of the Global NITAG Network (GNN) agreed that there is insufficient understanding of the impact of law on the functioning of NITAGs. Similarly, the Strategic Advisory Group of Experts on Immunization called for research into the variety of ways in which legislation and regulation have been used to promote immunization at a national level and to achieve different ends in relation to immunization and NITAG functioning. In answer to this call, the NITAG Environmental Scan (Project) was initiated. Drawing on scholarship around good governance, this article offers a comprehensive common assessment schema for critically and systematically approaching questions about NITAG governance and operation, applying that schema to the foundation instrument of the Côte d’Ivoire’s NITAG. It also reports on how well the schema is engaged by the NITAG foundation instruments in other GNN countries.

Social Justice in Pandemic Immunization Policy: We’re all in this together

Policy decisions regarding immunization during a pandemic are informed by the ethical understandings of policy makers. With the possibility that a vaccine might soon be available to mitigate the deadly COVID-19 pandemic, policy makers can consider learnings from past pandemic immunization campaigns. This critical analysis of three policy decisions made in Alberta, Canada, during the 2009 H1N1 influenza pandemic demonstrates the predominance of distributive justice principles and the problems that this created for vulnerable groups. Vulnerable groups identified in Alberta include rural and First Nations populations. We propose a social justice approach as a viable alternative to inform pandemic immunization policy and invite debate.

Strengthening National Immunization Technical Advisory Groups in resource-limited settings: current and potential linkages with polio national certification committees

Background Countries are transitioning assets and functions from polio eradication to integrated immunization and surveillance activities. We assessed the extent of linkages between and perceptions of National Immunization Technical Advisory Groups (NITAGs) and National Certification Committees (NCCs) for polio eradication to understand how linkages can be leveraged to improve efficiencies of these expert bodies. Methods During May 2017 to May 2018, we administered a 15-question survey to a NITAG chair or member and an NCC counterpart in all countries of the WHO Regions for Africa (AFR) and for the Eastern Mediterranean (EMR) that had both a NITAG and an NCC. Data were analysed using frequency distributions. Results Of countries with both a NITAG and an NCC (n = 44), the response rate was 92% (22/24) in AFR and 75% (15/20) in EMR. Some respondents reported being very familiar with the functions of the other technical bodies, 36% (8/22) for NITAG members and 38% (14/37) for NCC members. Over 85% (51/59) of respondents felt it was somewhat useful or very useful to strengthen ties between bodies. Nearly all respondents (98%, 58/59) felt that NCC expertise could inform measles and rubella elimination programmes. Conclusions We observed a broad consensus that human resource assets of NCCs may serve an important technical role to support national immunization policy-making. At this stage of the polio eradication initiative, countries should consider how to integrate the technical expertise of NCC members to reinforce NITAGs and maintain the polio essential functions, beginning in countries that have been polio-free for several years.