Safety of vaccines that have been kept outside of recommended temperatures: Reports to the Vaccine Adverse Event Reporting System (VAERS), 2008–2012

BackgroundVaccines should be stored and handled according to manufacturer specifications. Inadequate cold chain management can affect potency; but, limited data exist on adverse events (AE) following administration of vaccines kept outside of recommended temperatures.ObjectiveTo describe reports to the Vaccine Adverse Event Reporting System (VAERS) involving vaccines inappropriately stored outside of recommended temperatures and/or exposed to temperatures outside of manufacturer specifications for inappropriate amounts of time.MethodsWe searched the VAERS database (analytic period 2008–2012) for reports describing vaccines kept outside of recommended temperatures. We analyzed reports by vaccine type, length outside of recommended temperature and type of temperature excursion, AE following receipt of potentially compromised vaccine, and reasons for cold chain breakdown.ResultsWe identified 476 reports of vaccines kept outside of recommended temperatures; 77% described cluster incidents involving multiple patients. The most commonly reported vaccines were quadrivalent human papillomavirus (n = 146, 30%), 23-valent pneumococcal polysaccharide (n = 51, 11%), and measles, mumps, and rubella (n = 45, 9%). Length of time vaccines were kept outside of recommended temperatures ranged from 15 mins to 6 months (median 51 h). Most (n = 458, 96%) reports involved patients who were administered potentially compromised vaccines; AE were reported in 32 (7%), with local reactions (n = 21) most frequent. Two reports described multiple patients contracting diseases they were vaccinated against, indicating possible influenza vaccine failure. Lack of vigilance, inadequate training, and equipment failure were reasons cited for cold chain management breakdowns.ConclusionsOur review does not indicate any substantial direct health risk from administration of vaccines kept outside of recommended temperatures. However, there are potential costs and risks, including vaccine wastage, possible decreased protection, and patient and parent inconvenience related to revaccination. Maintaining high vigilance, proper staff training, regular equipment maintenance, and having adequate auxiliary power are important components of comprehensive vaccine cold chain management.     

A sex-role-preference model for HIV transmission among men who have sex with men in China

Background

Men who have sex with men (MSM) are much more likely to be infected with HIV than the general population. China has a sizable population of MSM, including gay, bisexual men, money boys and some rural workers. So reducing HIV infection in this population is an important component of the national HIV/AIDS prevention and control program.

Methods

We develop a mathematical model using a sex-role-preference framework to predict HIV infection in the MSM population and to evaluate different intervention strategies.

Results

An analytic formula for the basic reproduction ratio R₀ was obtained; this yields R₀ = 3.9296 in the current situation, so HIV will spread very fast in the MSM population if no intervention measure is implemented in a timely fashion. The persistence of HIV infection and the existence of disease equilibrium (or equilibria) are also shown. We utilized our model to simulate possible outcomes of antiretroviral therapy and vaccination for the MSM population. We compared the effects of these intervention measures under different assumptions about MSM behaviour. We also found that R₀ is a decreasing function of the death rate of HIV-infected individuals, following a power law at least asymptotically.

Conclusion

HIV will spread very fast in the MSM population unless intervention measures are implemented urgently. Antiretroviral therapy can have substantial impact on the reduction of HIV among the MSM population, even if disinhibition is considered. The effect of protected sexual behaviour on controlling the epidemic in the MSM population largely depends on the sex-ratio preference of different sub-populations.

     

Optimal provision of needle and syringe programmes for injecting drug users: A systematic review

The introduction of needle and syringe programmes (NSPs) during the 1980s is credited with averting an HIV epidemic in the United Kingdom and Australia, but hepatitis C (HCV) incidence continues to rise among injecting drug users (IDUs). NSPs incorporating additional harm reduction strategies have been highlighted as an approach that may impact on HCV incidence. This systematic review sought to determine which approaches to the organisation and delivery of NSPs are effective. Fifteen databases were searched for studies published since 1990. Two reviewers screened all titles and abstracts, and data extraction and quality assessment of individual studies were undertaken independently by one reviewer and checked for accuracy by a second. Sixteen studies met the criteria for inclusion. Based on 11 studies there was no evidence of an impact of different NSP settings or syringe dispensation policies on drug injecting behaviours, but mobile van sites and vending machines appeared to attract younger IDUs and IDUs with higher risk profiles. Two studies of interventions aimed at encouraging IDUs to enter drug treatment reported limited effects, but one study found that the combination of methadone treatment and full participation in NSPs was associated with a lower incidence of HIV and HCV. In addition, one study indicated that hospital-based programmes may improve access to health care services among IDUs. Currently, it is difficult to draw conclusions on ‘what works best’ within the range of harm reduction services available to IDUs. Further studies are required which have a stated aim of evaluating how different approaches to the organisation and delivery NSPs impact on effectiveness.     

Economic stress and HIV-associated health care utilization in a rural region of China: a qualitative study

China is experiencing an emerging HIV epidemic, primarily affecting the rural poor. For this group, the costs of staying healthy are often beyond their means. A qualitative study was undertaken with 20 HIV-positive people living in a rural area in Anhui, eastern China, 20 of their family members, 20 health care providers, and 20 uninfected villagers. In this area, the majority of HIV-positive people were infected through contaminated commercial plasma/blood donation procedures. In-depth interviews were conducted with participants to identify the barriers and enablers to accessing health care services for HIV. A major concern for affected villagers was the unaffordable costs of health care, which leads them to delay seeking services until symptoms are severe. Use of the health care system was also influenced by the availability of subsidized medications, distance to the health care centre and quality of available services. In contrast, participants were very positive about antiretroviral treatment services, which are now free. In the study area, access to health care is heavily subsidized, yet many still found these services unaffordable. More equitable and affordable services will be needed if China is to control its HIV epidemic.     

Vaccination coverage among social and healthcare workers in ten countries of Samu-social international sites

BackgroundWe aim to determine the vaccination coverage of social and healthcare workers in International sites of Samusocial, providing emergency care to homeless people, and to assess factors associated with having received necessary doses at adulthood.MethodsData on immunization coverage of social and healthcare workers were provided by a cross-sectional survey, conducted from February to April 2015 among 252 Samusocial workers in 10 countries. Vaccination status and characteristics of participants were collected through a self-administered questionnaire. Prevalence rate ratio (PRR) of vaccination status was calculated using Poisson regression models.ResultsAmong 252 Samusocial social and health workers who felt a questionnaire, median age was 39 years, 42.1% were female, 88.9% were in contact with homeless beneficiaries (19.1% health workers). Overall, 90.1% of Samusocial staff felt adult vaccinations was useful and 70.2% wished to receive booster doses in future. Vaccination coverage at adulthood was satisfactory for diphtheria and poliomyelitis (96%), but low for influenza (20.8%), meningococcus (50.5%), hepatitis B (56.3%), yellow fever (58.1%), measles (81.3%) and pertussis (90.7%). The main reasons for not having received vaccination booster doses were forgetting the dates of booster doses (38.4%) and not having received the information (13.5%). In adjusted analysis, prevalence of up-to-date for vaccination schedule was 35% higher among health workers than among social workers (aPRR = 1.35, 95%CI: 1.01–1.82, P = 0.05) and was 56% higher among workers who had a documentary evidence of vaccination than in those who did not (aPRR = 1.56, 95%CI: 1.19–2.02, P = 0.001).ConclusionsThe Samusocial International workers vaccine coverage at adulthood was insufficient and disparate by region. It is necessary to strengthen the outreach of this staff and increase immunization policy for hepatitis B, diphtheria, tetanus, and measles, as well as for yellow fever, rabies and meningococcal ACYW135 vaccines in at risk regions.