Coronavirus Disease Case Definitions, Diagnostic Testing Criteria, and Surveillance in 25 Countries with Highest Reported Case Counts.

We compared case definitions for suspected, probable, and confirmed coronavirus disease (COVID-19), as well as diagnostic testing criteria, used in the 25 countries with the highest reported case counts as of October 1, 2020. Of the identified countries, 56% followed World Health Organization (WHO) recommendations for using a combination of clinical and epidemiologic criteria as part of the suspected case definition. A total of 75% of identified countries followed WHO recommendations on using clinical, epidemiologic, and diagnostic criteria for probable cases; 72% followed WHO recommendations to use PCR testing to confirm COVID-19. Finally, 64% of countries used testing eligibility criteria at least as permissive as WHO. We observed marked heterogeneity in testing eligibility requirements and in how countries define a COVID-19 case. This heterogeneity affects the ability to compare case counts, transmission, and vaccine effectiveness, as well as estimates derived from case surveillance data across countries.

Monitoring and Validation of the Global Replacement of tOPV with bOPV, April-May 2016.

The phased withdrawal of oral polio vaccine (OPV) associated with the Polio Eradication and Endgame Strategic Plan 2013-2018 began with the synchronized global replacement of trivalent OPV (tOPV) with bivalent OPV (bOPV) during April - May 2016, a transition referred to as the "switch." The World Health Organization's (WHO) Strategic Advisory Group of Experts (SAGE) on Immunization recommended conducting this synchronized switch in all 155 OPV-using countries and territories (which collectively administered several hundred million doses of tOPV each year via several hundred thousand facilities) to reduce risks of re-emergence of vaccine-derived polioviruses. Safe execution of this switch required implementation of an associated independent monitoring strategy, the primary objective of which was verification that tOPV was no longer available for administration post-switch. This strategy had to be both practical and rigorous such that tOPV withdrawal could be reasonably employed and confirmed in all countries and territories within a discreet timeframe. Following these principles, WHO recommended that designated monitors in each of the 155 countries and territories visit all vaccine stores as well as a 10% sample of highest-risk health facilities within two weeks of the national switch date, removing any tOPV vials found. National governments were required to provide the WHO with formal validation of execution and monitoring of the switch. In practice, all countries reported cessation of tOPV by 12 May 2016 and 95% of countries and territories submitted detailed monitoring data to WHO. According to these data, 272 out of 276 (99%) national stores, 3,741 out of 3.968 (94%) regional stores, 16,144 out of 22,372 (72%) district level stores, and 143,050 out of 595,401 (24%) of health facilities were monitored. These data, along with field reports suggest that monitoring and validation of the switch was efficient and effective, and that the strategies used during the process could be adapted to future stages of OPV withdrawal.

Disposing of Excess Vaccines After the Withdrawal of Oral Polio Vaccine.

Until recently, waste management for national immunization programs was limited to sharps waste, empty vaccine vials, or vaccines that had expired or were no longer usable. However, because wild-type 2 poliovirus has been eradicated, the World Health Organization's (WHO's) Strategic Advisory Group of Experts on Immunization deemed that all countries must simultaneously cease use of the type 2 oral polio vaccine and recommended that all countries and territories using oral polio vaccine (OPV) "switch" from trivalent OPV (tOPV; types 1, 2, and 3 polioviruses) to bivalent OPV (bOPV; types 1 and 3 polioviruses) during a 2-week period in April 2016. Use of tOPV after the switch would risk outbreaks of paralysis related to type 2-circulating vaccine-derived poliovirus (cVDPV2). To minimize risk of vaccine-derived polio countries using OPV were asked to dispose of all usable, unexpired tOPV after the switch to bOPV. In this paper, we review the rationale for tOPV disposal and describe the global guidelines provided to countries for the safe and appropriate disposal of tOPV. These guidelines gave countries flexibility in implementing this important task within the confines of their national regulations, capacities, and resources. Steps for appropriate disposal of tOPV included removal of all tOPV vials from the cold chain, placement in appropriate bags or containers, and disposal using a recommended approach (ie, autoclaving, boiling, chemical inactivation, incineration, or encapsulation) followed by burial or transportation to a designated waste facility. This experience with disposal of tOPV highlights the adaptability of national immunization programs to new procedures, and identifies gaps in waste management policies and strategies with regard to disposal of unused vaccines. The experience also provides a framework for future policies and for developing programmatic guidance for the ultimate disposal of all OPV after the eradication of polio.

Administering Multiple Injectable Vaccines During a Single Visit-Summary of Findings From the Accelerated Introduction of Inactivated Polio Vaccine Globally.

Background: In 2013, the World Health Organization's (WHO's) Strategic Advisory Group of Experts (SAGE) recommended that all 126 countries using only oral polio vaccine (OPV) introduce at least 1 dose of inactivated polio vaccine (IPV) into their routine immunization schedules by the end of 2015. In many countries, the addition of IPV would necessitate delivery of multiple injectable vaccines (hereafter, "multiple injections") during a single visit, with infants receiving IPV alongside pentavalent vaccine (which covers diphtheria, tetanus, and whole-cell pertussis; hepatitis B; and Haemophilus influenzae type b) and pneumococcal vaccine. Unanticipated concerns emerged from countries over acceptability of multiple injections, sites of administration, and safety. We contextualized the issues surrounding multiple injections by documenting concerns associated with administration of ≥3 injections, existing evidence in the published literature, and findings of a systematic review on administration practices and techniques. Methods: Concerns associated with multiple-injection visits were documented from meetings and personal communications with immunization program managers. Published literature on the acceptability of multiple injections by providers and caregivers was summarized, and a systematic review of the literature on administration practices was completed on the following topics: spacing between injection sites (ie, vaccine spacing), site of injection, route of injection, and procedural preparedness. WHO and United Nations Children's Fund data from 2013-2015 were used to assess multiple-injection visits included in national immunization schedules. Results: Healthcare provider and caregiver attitudes and practices indicated concerns about infant pain, potential adverse effects, and uncertainty about vaccine effectiveness with multiple-injection visits. Published literature reinforced the record of safety and acceptance of the recommended schedule of IPV by the SAGE, but the evidence was largely from developed countries. Parental acceptance of multiple injections was associated with a positive provider recommendation to the caregiver. Findings of the systematic review identified that the intramuscular route is preferred over the subcutaneous route for vaccine administration and that the vastus lateralis muscle is preferred over the deltoid muscle for intramuscular injections. Recommendations on vaccine spacing and procedural preparedness were based on practical necessities, but comparative evidence was not identified. During 2013-2015, 85 countries added IPV to their immunization schedules, 46 (55%) of which adopted a schedule resulting in 3 injectable vaccines being administered in a single visit. Conclusion: The multiple-injection experience identified gaps in guidance for future vaccine introductions. Global partner organizations quickly mobilized to assess, document, and communicate the existing global experience on multiple-injection visits. This evidence-based approach provided reassurance to opinion leaders, health workers, and professional societies, thus encouraging uptake of IPV as a second or third injection in an accelerated manner globally.

Implementing the Synchronized Global Switch from Trivalent to Bivalent Oral Polio Vaccines-Lessons Learned From the Global Perspective.

In 2015, the Global Commission for the Certification of Polio Eradication certified the eradication of type 2 wild poliovirus, 1 of 3 wild poliovirus serotypes causing paralytic polio since the beginning of recorded history. This milestone was one of the key criteria prompting the Global Polio Eradication Initiative to begin withdrawal of oral polio vaccines (OPV), beginning with the type 2 component (OPV2), through a globally synchronized initiative in April and May 2016 that called for all OPV using countries and territories to simultaneously switch from use of trivalent OPV (tOPV; containing types 1, 2, and 3 poliovirus) to bivalent OPV (bOPV; containing types 1 and 3 poliovirus), thus withdrawing OPV2. Before the switch, immunization programs globally had been using approximately 2 billion tOPV doses per year to immunize hundreds of millions of children. Thus, the globally synchronized withdrawal of tOPV was an unprecedented achievement in immunization and was part of a crucial strategy for containment of polioviruses. Successful implementation of the switch called for intense global coordination during 2015-2016 on an unprecedented scale among global public health technical agencies and donors, vaccine manufacturers, regulatory agencies, World Health Organization (WHO) and United Nations Children's Fund (UNICEF) regional offices, and national governments. Priority activities included cessation of tOPV production and shipment, national inventories of tOPV, detailed forecasting of tOPV needs, bOPV licensing, scaling up of bOPV production and procurement, developing national operational switch plans, securing funding, establishing oversight and implementation committees and teams, training logisticians and health workers, fostering advocacy and communications, establishing monitoring and validation structures, and implementing waste management strategies. The WHO received confirmation that, by mid May 2016, all 155 countries and territories that had used OPV in 2015 had successfully withdrawn OPV2 by ceasing use of tOPV in their national immunization programs. This article provides an overview of the global efforts and challenges in successfully implementing this unprecedented global initiative, including (1) coordination and tracking of key global planning milestones, (2) guidance facilitating development of country specific plans, (3) challenges for planning and implementing the switch at the global level, and (4) best practices and lessons learned in meeting aggressive switch timelines. Lessons from this monumental public health achievement by countries and partners will likely be drawn upon when bOPV is withdrawn after polio eradication but also could be relevant for other global health initiatives with similarly complex mandates and accelerated timelines.

Improving the Science of Measles Prevention-Will It Make for a Better Immunization Program?

In a Perspective, Julie Garon and Walter Orenstein discuss Lessler and colleagues' modeling study on measles vaccination and the implications for triggered and routine immunization programs.

Cessation of Trivalent Oral Poliovirus Vaccine and Introduction of Inactivated Poliovirus Vaccine - Worldwide, 2016.

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis, transmission of the three types of wild poliovirus (WPV) has been sharply reduced (1). WPV type 2 (WPV2) has not been detected since 1999 and was declared eradicated in September 2015. Because WPV type 3 has not been detected since November 2012, WPV type 1 (WPV1) is likely the only WPV that remains in circulation (1). This marked progress has been achieved through widespread use of oral poliovirus vaccines (OPVs), most commonly trivalent OPV (tOPV), which contains types 1, 2, and 3 live, attenuated polioviruses and has been a mainstay of efforts to prevent polio since the early 1960s. However, attenuated polioviruses in OPV can undergo genetic changes during replication, and in communities with low vaccination coverage, can result in vaccine-derived polioviruses (VDPVs) that can cause paralytic polio indistinguishable from the disease caused by WPVs (2). Among the 721 polio cases caused by circulating VDPVs (cVDPVs*) detected during January 2006-May 2016, type 2 cVDPVs (cVDPV2s) accounted for >94% (2). Eliminating the risk for polio caused by VDPVs will require stopping all OPV use. The first stage of OPV withdrawal involved a global, synchronized replacement of tOPV with bivalent OPV (bOPV) containing only types 1 and 3 attenuated polioviruses, planned for April 18-May 1, 2016, thereby withdrawing OPV type 2 from all immunization activities (3). Complementing the switch from tOPV to bOPV, introduction of at least 1 dose of injectable, trivalent inactivated poliovirus vaccine (IPV) into childhood immunization schedules reduces risks from and facilitates responses to cVDPV2 outbreaks. All 155 countries and territories that were still using OPV in immunization schedules in 2015 have reported that they had ceased use of tOPV by mid-May 2016.(†) As of August 31, 2016, 173 (89%) of 194 World Health Organization (WHO) countries included IPV in their immunization schedules.(§) The cessation of tOPV use is a major milestone toward the global goal of eradicating polio; however, careful surveillance for polioviruses and prompt, aggressive responses to polio outbreaks are still needed to realize a polio-free world.

Cost of human papillomavirus vaccine delivery at district and health facility levels in Zimbabwe: A school-based vaccination program targeting multiple cohorts.

BACKGROUND: After a pilot project in 2014-15 Zimbabwe introduced the human papillomavirus (HPV) vaccine nationally in 2018 for girls aged 10-14 years through a primarily school-based vaccination campaign with two doses administered at 12-month intervals. In 2019, a first dose was delivered to a new cohort of girls in grade 5 of girls age 10 years if out-of-school (OOS), along with a second dose to the 2018 multiple cohorts. Additional effort was made to identify and mobilize OOS girls by Village Health Workers (VHWs) in the community. Zimbabwe reported 1,569,905 doses of HPV vaccine administered during the 2018 and 2019 campaigns. This analysis evaluated the cost of Zimbabwe's national HPV vaccine introduction. METHODS: A retrospective, incremental, ingredients-based cost analysis from the provider perspective was conducted in 2018 and 2019. Financial and economic cost data were collected at district and health facility levels using a two-stage cluster sampling approach and four cost dimensions: program activity, resource input, payer, and administrative level. Costs are presented in 2020 US$ in total and per dose. RESULTS: The total weighted costs for combined district and health facility administrative levels were US$ 828,731 (financial) and US$ 2,060,943 (economic). For service delivery, the total weighted cost per dose was US$ 0.16 (financial) and US$ 0.59 (economic). The program activities with the largest share of total weighted financial cost were training (37% of total) and service delivery (30%), while the largest shares of total weighted economic costs were service delivery (45%) and training (19%). Efforts by VHWs to reach OOS girls resulted in an additional US$ 2.99 in financial cost per dose and US$ 7.79 in economic cost per dose. CONCLUSION: The service delivery cost per dose was lower than that documented in the pilot program cost analysis in Zimbabwe and studies elsewhere, reflecting a campaign delivery approach that spread fixed costs over a large vaccination cohort. The additional cost of reaching OOS girls with the HPV vaccine was documented for the first time in low- and middle-income countries, which may provide information on potential costs for other countries.

National introduction of HPV vaccination in Senegal-Successes, challenges, and lessons learned.

Following successful school-based demonstration programs in 2014-2016, the human papillomavirus (HPV) vaccine was introduced nationwide in Senegal for 9-year-old girls in 2018, using a routine service delivery strategy at health facilities, schools, and other outreach sites. We reviewed the HPV vaccine introduction in Senegal to understand the successes, challenges, and lessons learned. Focusing on three key domains (program decision-making, planning, and implementation), we conducted ten semi-structured interviews during 2019-2020 with purposively selected national-level stakeholders (government, expert advisory committee, key technical and implementation partners) and comprehensive desk reviews of country documents on HPV vaccine introduction. Due to the global HPV vaccine shortage, the introduction was limited to a single-age cohort; therefore, 9-year-old girls were chosen. This strategy enabled Senegal to potentially reach more girls in primary education because school enrolment rates decline thereafter. Vaccination through routine delivery platforms (i.e., health facility, school-based, and community outreach) was perceived to be more cost-effective than a campaign approach. High-level political commitment and collaborations between immunization and education partners were frequently cited by key informants as reasons for a successful vaccine introduction. All key informants reported that the health care worker (HCW) strike, rumors, and vaccine hesitancy negatively impacted the introduction. Other challenges noted included insufficient information on attitudes towards HPV vaccination among HCWs, teachers, and community members. Senegal successfully introduced HPV vaccine into the national immunization schedule, using a routine delivery strategy. Strong leadership and a multi-sectoral approach likely contributed to this success. To build sustainability of the HPV vaccination program in the future, it is important to improve the understanding and engagement among all stakeholders, including HCWs and community members, and to strengthen and innovate communication and crisis management strategies. To better understand the efficiency and effectiveness of Senegal's vaccination strategy, additional assessments of the operational costs and coverage achieved are needed.

Multiple cohort HPV vaccination in Zimbabwe: 2018-2019 program feasibility, awareness, and acceptability among health, education, and community stakeholders.

INTRODUCTION: Zimbabwe introduced human papillomavirus (HPV) vaccine nationally in May 2018, targeting multiple cohorts (girls aged 10-14 years) through a school-based vaccination campaign. One year later, the second dose was administered to the multiple cohorts concurrently with the first dose given to a new single cohort of girls in grade 5. We conducted cross-sectional surveys among health workers, school personnel, and community members to assess feasibility of implementation, training, social mobilization, and community acceptability. METHODS: Thirty districts were selected proportional to the volume of the HPV vaccine doses delivered in 2018; two health facilities were randomly selected within each district. One health worker, school health coordinator, village health worker, and community leader were surveyed at each selected health facility and surrounding area during January-February 2020, using standard questionnaires. Descriptive analysis was completed across groups. RESULTS: There were 221 interviews completed. Over 60% of health workers reported having enough staff to carry out vaccination sessions in schools while maintaining routine vaccination services in health facilities. All school health coordinators felt the HPV vaccine should be delivered in schools in the future. Knowledge of the correct target cohort eligibility decreased from 91% in 2018 to 50% in 2020 among health workers. Understanding of HPV infection and use of HPV vaccine for cervical cancer prevention was above 90% for all respondents. Forty-two percent of respondents reported hearing rumors about the HPV vaccine, primarily regarding infertility and safety. CONCLUSIONS: Findings demonstrate the presence of highly knowledgeable staff at health facilities and schools, strong community acceptance, and a school-based HPV program considered feasible to implement in Zimbabwe. However, misunderstandings regarding target eligibility and rumors persist, which can impact vaccine uptake and coverage. Continued social mobilization efforts to maintain community demand and training on eligibility were recommended. Integration, partnerships, and resource mobilization are also needed to ensure program sustainability.

Feasibility and acceptability of nationwide HPV vaccine introduction in Senegal: Findings from community-level cross-sectional surveys, 2020.

In Senegal, cervical cancer is the most common cancer among women and the leading cause of morbidity and mortality from all cancers. In 2018, Senegal launched a national human papillomavirus (HPV) vaccination program with Gavi, the Vaccine Alliance (Gavi), support. HPV vaccination was incorporated into the national immunization program as a two-dose schedule, with a 6-12-month interval, to nine-year-old girls via routine immunization (RI) services at health facilities, schools and community outreach services throughout the year. During February to March 2020, we conducted interviews to assess the awareness, feasibility, and acceptability of the HPV vaccination program with a cross-sectional convenience sample of healthcare workers (HCWs), school personnel, community healthcare workers (cHCWs), parents, and community leaders from 77 rural and urban health facility catchment areas. Participants were asked questions on HPV vaccine knowledge, delivery, training, and community acceptability of the program. We conducted a descriptive analysis stratified by respondent type. Data were collected from 465 individuals: 77 HCW, 78 school personnel, 78 cHCWs, 152 parents, and community leaders. The majority of HCWs (83.1%) and cHCWs (74.4%) and school personnel (57.7%) attended a training on HPV vaccine before program launch. Of all respondents, most (52.5-87.2%) were able to correctly identify the target population. The majority of respondents (60.2-77.5%) felt that the vaccine was very accepted or accepted in the community. Senegal's HPV vaccine introduction program, among the first national programs in the African region, was accepted by community stakeholders. Training rates were high, and most respondents identified the target population correctly. However, continued technical support is needed for the integration of HPV vaccination as a RI activity for this non-traditional age group. The Senegal experience can be a useful resource for countries planning to introduce the HPV vaccine.

Ultrasound and cytological characteristics of non-invasive follicular thyroid neoplasm with papillary-like nuclear features compared to papillary carcinomas.

INTRODUCTION: NIFTP (non-invasive follicular thyroid neoplasm with papillary-like nuclear features, formerly non-invasive encapsulated follicular variant of papillary thyroid carcinoma) has been removed from the carcinoma category because of its indolent character and good prognosis. This change impacts clinical and surgical management, since these tumors no longer require total thyroidectomy, or complementary radioactive iodine therapy for <4cm tumor. The aim of the present study was to identify preoperative ultrasound and cytological differences between NIFTP and papillary thyroid carcinoma (PTC). MATERIALS AND METHODS: A retrospective study included 81 patients who underwent total thyroidectomy or thyroid lobectomy with histologic diagnosis of PTC, NIFTP or invasive follicular variant of PTC (IFVPTC) between January 1st, 2016 and May 31st, 2018. Ultrasound and cytological data were analyzed and compared between NIFTP and non-NIFTP (PTC and invasive follicular variant of PTC). RESULTS: Fourteen NIFTPs, 67 PTCs, including 20 IFVPTCs, were included. In comparison with non-NIFTP PTC, nodules in NIFTP were more often isoechoic (69.2% vs. 17.4%; P=0.0007), with smooth borders (92.3% vs. 31.1%; P=0.0001) and TI-RADS score 2, 3 or 4a. Cytologically, NIFTPs were mainly in categories AUS/FLUS, FN and SusM of the Bethesda System for Reporting Thyroid Cytopathology. Only nuclear pseudo-inclusions were significantly associated with non-NIFTP (P=0.0031). CONCLUSION: NIFTP appears non-suspect on preoperative ultrasound and indeterminate on cytology. These differences with respect to PTC can guide diagnosis and surgical treatment.

Community-based household assessment of human papillomavirus (HPV) vaccination coverage and acceptability - HPV vaccine demonstration program, Cambodia - 2017.

BACKGROUND: In 2017, the Cambodia Ministry of Health introduced human papillomavirus (HPV) vaccine through primarily school-based vaccination targeting 9-year-old girls. Vaccination with a two-dose series of HPV vaccine took place in six districts in two provinces as a demonstration program, to better understand HPV vaccine delivery in Cambodia. METHODS: We conducted a community-based coverage survey using a one-stage sampling design to evaluate dose-specific vaccination coverage among eligible girls (those born in 2007 and residents in the areas targeted by the campaign). The household-level survey also assessed factors associated with vaccine acceptability and communication strategies. Trained data collectors interviewed caregivers and girls using a standard questionnaire; vaccination cards and health facility records were reviewed. RESULTS: Of the 7594 households visited in the two provinces, 315 girls were enrolled in the survey (188 in Siem Reap; 127 in Svay Rieng). Documented two-dose HPV vaccination coverage was 84% (95% confidence interval [CI]: 78-88%) overall [85% (95% CI: 78-90%) in Siem Reap; 82% (95% CI: 73-88%) in Svay Rieng.] Almost all girls (>99%) were reported to be enrolled in school and over 90% of respondents reported receipt of vaccine in school. Knowledge of HPV infection and associated diseases was poor among caregivers and girls; however, 58% of caregivers reported "protection from cervical cancer" as the primary reason for the girl receiving vaccine. No serious adverse events after immunization were reported. CONCLUSIONS: The HPV vaccine demonstration program in Cambodia achieved high two-dose coverage among eligible girls in both provinces targeted for vaccination in 2017, through primarily school-based vaccination. High school enrollment and strong microplanning and coordination were seen throughout the campaign. Cambodia will use lessons learned from this demonstration program to prepare for national introduction of HPV vaccine.

The Global Vaccine Action Plan - insights into its utility, application, and ways to strengthen future plans.

BACKGROUND: The pace of global progress must increase if the Global Vaccine Action Plan (GVAP) goals are to be achieved by 2020. We administered a two-phase survey to key immunization stakeholders to assess the utility and application of GVAP, including how it has impacted country immunization programs, and to find ways to strengthen the next 10-year plan. METHODS: For the Phase I survey, an online questionnaire was sent to global immunization stakeholders in summer 2017. The Phase II survey was sent to regional and national immunization stakeholders in summer 2018, including WHO Regional Advisors on Immunization, Expanded Programme on Immunization managers, and WHO and UNICEF country representatives from 20 countries. Countries were selected based on improvements (10) versus decreases (10) in DTP3 coverage from 2010 to 2016. RESULTS: Global immunization stakeholders (n = 38) cite global progress in improving vaccine delivery (88%) and engaging civil society organizations as advocates for vaccines (83%). Among regional and national immunization stakeholders (n = 58), 70% indicated reaching mobile and underserved populations with vaccination activities as a major challenge. The top ranked activities for helping country programs achieve progress toward GVAP goals include improved monitoring of vaccination coverage and upgrading disease surveillance systems. Most respondents (96%) indicated GVAP as useful for determining immunization priorities and 95% were supportive of a post-2020 GVAP strategy. CONCLUSIONS: Immunization stakeholders see GVAP as a useful tool, and there is cause for excitement as the global immunization community looks toward the next decade of vaccines. The next 10-year plan should attempt to increase political will, align immunization activities with other health system agendas, and address important issues like reaching mobile/migrant populations and improving data reporting systems.

Drug-induced aseptic meningitis: a mini-review.

Aseptic meningitis associates a typical clinical picture of meningitis with the absence of bacterial or fungal material in the cerebrospinal fluid. Drug-induced aseptic meningitis (DIAM) may be due to two mechanisms: (i) a direct meningeal irritation caused by the intrathecal administration of drugs and (ii) an immunologic hypersensitivity reaction to a systemic administration. If the direct meningeal irritation allows a rather easy recognition, the immunologic hypersensitivity reaction is a source of challenging diagnostics. DIAM linked to a systemic treatment exerts typically an early onset, usually within a week. This period can be shortened to a few hours in case of drug rechallenge. The fast and spontaneous regression of clinical symptoms is usual after stopping the suspected drug. Apart from these chronological aspects, no specific clinical or biological parameters are pathognomonic. CSF analysis usually shows pleiocytosis. The proteinorachia is increased while glycorachia remains normal. Underlying pathologies can stimulate the occurrence of DIAM. Thus, systemic lupus erythematosus appears to promote DIAM during NSAID therapy, especially ibuprofen-based one. Similarly, some patients with chronic migraine are prone to intravenous immunoglobulin-induced aseptic meningitis. DIAM will be mainly evoked on chronological criteria such as rapid occurrence after initiation, rapid regression after discontinuation, and recurrence after rechallenge of the suspected drug. When occurring, positive rechallenge may be very useful in the absence of initial diagnosis. Finally, DIAM remains a diagnosis of elimination. It should be suggested only after all infectious causes have been ruled out.

The polio endgame: rationale behind the change in immunisation.

The decades long effort to eradicate polio is nearing the final stages and oral polio vaccine (OPV) is much to thank for this success. As cases of wild poliovirus continue to dwindle, cases of paralysis associated with OPV itself have become a concern. As type-2 poliovirus (one of three) has been certified eradicated and a large proportion of OPV-related paralysis is caused by the type-2 component of OPV, the World Health Assembly endorsed the phased withdrawal of OPV and the introduction of inactivated polio vaccine (IPV) into routine immunisation schedules as a crucial step in the polio endgame plan. The rapid pace of IPV scale-up and uptake required adequate supply, planning, advocacy, training and operational readiness. Similarly, the synchronised switch from trivalent OPV (all three types) to bivalent OPV (types 1 and 3) involved an unprecedented level of global coordination and country commitment. The important shift in vaccination policy seen through global IPV introduction and OPV withdrawal represents an historical milestone reached in the polio eradication effort.

The Need and Potential of Inactivated Poliovirus Vaccine.

As the polio endgame progresses, the world will increasingly rely on inactivated polio vaccine (IPV) for protection against polio (wild and vaccine-related) and for risk mitigation during the phased removal of oral polio vaccine (OPV). IPV has already been introduced in most countries and strategies are underway to ensure the remaining OPV-only using countries succeed in introducing IPV in light of operational challenges. Questions remain as to the ideal dosing schedule for IPV in developing countries as well as the length of time for IPV to be administered beyond certification of eradication of wild polioviruses and total OPV withdrawal. IPV policies will likely evolve and new technologies will become available to meet unforeseen needs during this historical and unprecedented public health endeavor. Pediatricians in India have a crucial role to play in this global effort by supporting the overall polio eradication strategy and ensuring that all targeted children in India receive IPV.

Polio endgame: the global switch from tOPV to bOPV.

Globally, polio cases have reached an all-time low, and type 2 poliovirus (one of three) is eradicated. Oral polio vaccine (OPV) has been the primary tool, however, in rare cases, OPV induces paralysis. In 2013, the World Health Assembly endorsed the phased withdrawal of OPV and introduction of inactivated poliovirus vaccine (IPV) into childhood routine immunization schedules. Type 2 OPV will be withdrawn through a globally synchronized "switch" from trivalent OPV (all three types) to bivalent OPV (types 1 and 3). The switch will happen in 155 OPV-using countries between April 17(th) and May 1(st), 2016. Planned activities to reduce type 2 outbreak risks post-switch include the following: tOPV campaigns to increase type 2 immunity prior to the switch, monovalent OPV2 stockpiling to respond to outbreaks should they occur, containment of both wild and vaccine type 2 viruses, enhanced acute flaccid paralysis (AFP) and environmental surveillance, outbreak response protocols, and ensured access to IPV and bivalent OPV.

Understanding the host-pathogen interaction saves lives: lessons from vaccines and vaccinations.

Vaccines are one of the most successful and cost-effective public health tools employed to date, yet these benefits are only realized when the life-saving intervention reaches each and every targeted individual. Vaccine development is prioritized based on a number of factors such as health burden, feasibility, and determination of potential target populations. But only through an arduous process of pre-clinical development and progressive clinical trials does a vaccine become licensed and recommended for use. Once used in a wider and more diverse population safety issues, long-term impact and other unintended outcomes may become apparent, influencing policy modification. This commentary explores the role host-pathogen interaction plays in vaccine development and the operational and policy considerations that may impact vaccine success post-licensure.