Background: Wild type 2 poliovirus was last observed in 1999. The Sabin-strain oral polio vaccine type 2 (OPV2) was critical to eradication, but it is known to revert to a neurovirulent phenotype, causing vaccine-associated paralytic poliomyelitis. OPV2 is also transmissible and can establish circulating lineages, called circulating vaccine-derived polioviruses (cVDPVs), which can also cause paralytic outbreaks. Thus, in April 2016, OPV2 was removed from immunization activities worldwide. Interrupting transmission of cVDPV2 lineages that survive cessation will require OPV2 in outbreak response, which risks seeding new cVDPVs. This potential cascade of outbreak responses seeding VDPVs, necessitating further outbreak responses, presents a critical risk to the OPV2 cessation effort.
Methods: The EMOD individual-based disease transmission model was used to investigate OPV2 use in outbreak response post-cessation in West African populations. A hypothetical outbreak response in northwest Nigeria is modeled, and a cVDPV2 lineage is considered established if the Sabin strain escapes the response region and continues circulating 9 months post-response. The probability of this event was investigated in a variety of possible scenarios.
Results: Under a broad range of scenarios, the probability that widespread OPV2 use in outbreak response (~2 million doses) establishes new cVDPV2 lineages in this model may exceed 50% as soon as 18 months or as late as 4 years post-cessation.
Conclusions: The risk of a cycle in which outbreak responses seed new cVDPV2 lineages suggests that OPV2 use should be managed carefully as time from cessation increases. It is unclear whether this risk can be mitigated in the long term, as mucosal immunity against type 2 poliovirus declines globally. Therefore, current programmatic strategies should aim to minimize the possibility that continued OPV2 use will be necessary in future years: conducting rapid and aggressive outbreak responses where cVDPV2 lineages are discovered, maintaining high-quality surveillance in all high-risk settings, strengthening the use of the inactivated polio vaccine as a booster in the OPV2-exposed and in routine immunization, and gaining access to currently inaccessible areas of the world to conduct surveillance.
Background: The frequency of EoE has been increasing in Northern Hemisphere cohorts, yet there is a scarcity of data in our region. Regional climatic factors, and lifestyle habits may influence the presentation of EoE, and appropriate management is crucial to prevent complications. WIth this is mind we undertook the first comprehensive multisite study of EoE in Australasian children.
Polyunsaturated fatty acids (PUFAs) are fatty acids, containing more than one double bond and have both anti-inflammatory properties and inhibit tumor progression effects as well as carcinogenic properties. There is inconclusive evidence regarding the effect of PUFA intake on gastric cancer in diverse populations. We, therefore, aimed to determine the association between PUFA intake and risk of gastric cancer in a hospital-based case-control study comprising 1182 incident cases of gastric cancer and 2965 controls in Vietnam.
Limited meta-analytical research has examined the epidemiology of child sexual abuse (CSA) victimization among Chinese children and adolescents over the past two decades. It is crucial to evaluate how the incidence of CSA has changed over time in response to the significant policy and sociocultural changes since 2013. This study employed a cross-temporal meta-analysis to explore the trend of CSA victimization among Chinese children and adolescents from 2000 to 2022.
