Critical Needs & Gaps Report
CURRENT VACCINES FOR TICK-BORNE DISEASES AND VACCINE DEVELOPMENT
Prevention
The societal burden of tick-borne diseases (TBDs) is substantial. In the United States alone, every year this group of diseases produces tens of thousands of illnesses, many of which are severe and result in hospitalization, long-term sequelae, including disabilities or deaths. Research efforts have been focused on ameliorating the symptoms and consequences of disease through treatment. However, the development, deployment, and evaluation of strategies to prevent the occurrence of TBDs should also be a major area of scientific inquiry. This is one aspect of the debate about tick-borne diseases where there is no controversy. Prevention of disease is far preferable to treating the short- and long-term consequences once they occur.
The incidence rate of all of the diseases discussed in this workshop has been on the increase. They have also been expanding in geographic range, and new human tick-borne pathogens continue to be recognized. These trends result in an ever-larger number of persons requiring treatment, placing a greater financial impact on the healthcare system and individual patients, and, ultimately, a greater burden on society. The escalating burden of TBDs is a clear demonstration that the available prevention measures have been ineffective. Whether this is because they simply do not work or because they have been underused is far less clear. But a wider array of simple and effective prevention modalities would be very beneficial and would, it is hoped, change the current trajectory of TBD incidence.
Prevention measures can be divided into two categories: Pharmacologic preventive measures such as antibiotic prophylaxis or vaccines, and non-pharmacologic interventions such as behavior change or tick-targeted strategies (e.g., tick checks or tick reduction). In this workshop, information was presented for both categories, but there was not enough time to cover the entire range of available or potential approaches. Two presentations addressed current and future opportunities for vaccine development. One presentation addressed the role and effectiveness of behavior change and another addressed vector-control strategies.
CURRENT VACCINES FOR TICK-BORNE DISEASES AND VACCINE DEVELOPMENT
Jere W. McBride, Ph.D., M.S., Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston
Currently, no tick-borne disease vaccines for humans are licensed in the United States. The U.S. Food and Drug Administration licensed a vaccine for Lyme disease in 1998 and it was withdrawn from the market in 2002. While the vaccine—based on outer surface protein A (OspA) emulsified in aluminum hydroxide adjuvant—prevented transmission of Borrelia burg-dorferi from ticks to humans by killing spirochetes in ticks, three doses were needed to provide 80 percent protection against infection. A number of problems contributed to the withdrawal of the vaccine. The antibody titers did not persist for long time periods, which required individuals to receive multiple boosters to maintain protective immunity. Furthermore, a number of autoimmune-related side effects, including arthritis and neuropathology, were reported to possibly be associated with the vaccine (Schuijt et al., 2011). A
short stretch of amino acids in OspA with the potential for molecular mimicry with human LFA-1 (lymphocyte function associated antigen) was identified as a possible cause for the autoimmune-related responses, but this finding remains controversial (Steere et al., 2001; Ball et al., 2009). In Europe, current efforts are focused on developing vaccines with a modified OspA that does not contain the sequence linked to autoimmune responses. Other vaccines for Borrelia are in varying stages of development as either single- or multiple-antigen vaccines that include OspB, OspC, or DNA-binding protein HU-alpha.
Link Here- pg. 2
http://www.ncbi.nlm.nih.gov/books/NBK57027/
Curr Med Chem. 2011;18(17):2630-7.
Aluminum vaccine adjuvants: are they safe?
Source
Neural Dynamics Research Group, Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, V5Z 1L8, Canada. lucijat77@gmail.com
Abstract
Aluminum is an experimentally demonstrated neurotoxin and the most commonly used vaccine adjuvant. Despite almost 90 years of widespread use of aluminum adjuvants, medical science's understanding about their mechanisms of action is still remarkably poor. There is also a concerning scarcity of data on toxicology and pharmacokinetics of these compounds. In spite of this, the notion that aluminum in vaccines is safe appears to be widely accepted.
Experimental research, however, clearly shows that aluminum adjuvants have a potential to induce serious immunological disorders in humans. In particular, aluminum in adjuvant form carries a risk for autoimmunity, long-term brain inflammation and associated neurological complications and may thus have profound and widespread adverse health consequences.
In our opinion, the possibility that vaccine benefits may have been overrated and the risk of potential adverse effects underestimated, has not been rigorously evaluated in the medical and scientific community. We hope that the present paper will provide a framework for a much needed and long overdue assessment of this highly contentious medical issue.
PMID:
21568886
Aluminum Adjuncts in Vaccines- Is it Safe?