Immunosuppression and vaccinations

Immunocompromised subjects have a higher risk of infection. Some infectious risks could be controlled by vaccination, carried out according to normal schedules, in the absence of effective curative treatment. According to the type of immunodeficiency and its severity, certain vaccines may be recommended, others should be avoided and still others may be used with no particular risk. Thus, in immuno-compromised subjects, vaccines consisting of inactivated, inert or dead microorganisms are indicated. In contrast, those consisting of live microbes are not recommended for several reasons: 1) there is a risk that the immunocompromised host will be unable to control infection with the vaccine; 2) there is a risk of an increase in viral replication, particularly in HIV-infected subjects and 3) there is a risk that the response of the immune system will be poor. HIV-infected individuals now account for most of the cases of secondary immuno-deficiency, following the emergence of AIDS in 1980. They are increasing in number, especially in developing countries, where antiretroviral treatment is not widely available. In this context, vaccinations against transmissible childhood viral and bacterial diseases (e.g. measles and polio) with a high prevalence is advisable, with modifications according to the risk of contagion and the degree of immunodeficiency. However, these vaccines do not target opportunist infections, the prognosis of which is poor and against which we have no vaccines. Other vaccines are recommended only for immunocompromised subjects visiting countries with specific epidemiological situations (endemic or epidemic diseases) or if vaccination is required by the country visited.     

Immune interference after sequential alphavirus vaccine vaccinations

We compared the effect of order of administration of investigational alphavirus vaccines on neutralizing antibody response. Volunteers who received the inactivated eastern and western equine encephalitis (EEE and WEE) vaccines before live attenuated Venezuelan (VEE) vaccine had significantly lower rates of antibody response than those receiving VEE vaccine before EEE and WEE vaccines (66.7% vs. 80.6%; p = 0.026). The odds of having a VEE antibody non-response among those initially receiving EEE and WEE vaccines, adjusted for gender, were significant (odds ratio [OR] = 2.20; 95% CI = 1.2–4.1 [p = 0.0145]) as were the odds of non-response among females adjusted for group (OR = 1.81; 95% CI = 1.2–2.7 [p = 0.0037]). Antibody interference and gender effect have major implications for vaccine strategy among those receiving multiple alphavirus vaccines and those developing next generation vaccines for these threats.     

Statewide impact of pharmacist-delivered adult influenza vaccinations

BACKGROUND: Oregon law has allowed pharmacists to provide adult immunizations since 2000. Every vaccination delivered must be reported to the state health department. Previous reports indicate that pharmacists vaccinate individuals unlikely to receive vaccinations elsewhere. METHODS: Administration reports were analyzed in 2005 for the first three influenza seasons (2000 to 2003). The number of pharmacies participating, type and quantity of vaccinations, and county where provided were analyzed. RESULTS: A total of 13,116 adult patients received influenza vaccinations during 2000-2001 at 56 pharmacies. The number of pharmacies participating increased to 88 and 132, and vaccinations provided to 25,785 and 30,218 in the next two seasons, respectively. The mean number of vaccinations per pharmacy was 250 (standard deviation 236) for the 3-year period. Rural counties accounted for 28.4% of influenza vaccinations. CONCLUSIONS: Pharmacists provided a substantial number of influenza vaccinations during this 3-year period. More than one quarter of the vaccinations were provided in rural counties.     

Epidemiological assessment of an effectiveness of vaccinations

The study deals with the notion of the effectiveness of vaccination in relation to vaccine efficacy and the performance of the vaccination programs. The types of epidemiological studies used in assessment of vaccine effectiveness are presented and listed are the most common sources of bias in those studies. Basic formulas for calculation of vaccine efficiency coefficient are given as applied for cohort and case-control studies. Ways of estimation of vaccine effectiveness in outbreaks of epidemics are presented in relation to the degree of vaccine coverage and herd immunity effect. Effectiveness is analyzed as one of the many aspects in evaluation of the epidemiological impact of vaccinations.     

Financing vaccinations - The South African experience

South Africa provides a useful country case study for financing vaccinations. It has been an early adopter of new vaccinations and has financed these almost exclusively from domestic resources, largely through general taxation. National vaccination policy is determined by the Department of Health, based on advice from a national advisory group on immunisation. Standard health economic criteria of effectiveness, cost-effectiveness, affordability and burden of disease are used to assess whether new vaccinations should be introduced. Global guidelines and the advice of local and international experts are also helpful in making the determination to introduce new vaccines. In terms of recent decisions to introduce new vaccines against pneumococcal disease and rotavirus diarrhoea in children, the evidence has proved unequivocal. Universal rollout has been implemented even though this has led to a fivefold increase in national spending on vaccines. The total cost to government remains below 1-1.5% of public expenditures for health, which is viewed by the South African authorities as affordable and necessary given the number of lives saved and morbidity averted. To manage the rapid increase in domestic spending, efforts have been made to scale up coverage over several years, give greater attention to negotiating price reductions and, in some cases, obtain initial donations or frontloaded deliveries to facilitate earlier universal rollout. There has been strong support from a wide range of stakeholders for the early introduction of new generation vaccines.