Introduction
Introduction
Challenges of vaccination
Rationale for the development of national guidelines
Scope of guideline
The introduction of vaccines has been one of the most cost-effective strategies to prevent infectious diseases in humans1. It is estimated that vaccines save 2-3 million lives globally each year (WHO and UNICEF 2005). Vaccines are critical in preventing vaccine-preventable diseases (VPDs), particularly among immunocompromised individuals such as those with HIV infection. HIV-infected individuals have impaired host defence (cellular and humoral immunity) and hence have a greater risk and severity of vaccine-preventable diseases than the non-immunocompromised populations 2.
Effective antiretroviral therapy (ART) has resulted in HIV infection becoming a chronic manageable illness. Despite ART, systemic inflammation and immune activation persists in HIV-infected individuals and is associated with adverse health outcomes 3. Furthermore, immune reconstitution is incomplete following ART initiation, which might include absence of underlying memory responses previously induced through natural infection or early childhood vaccination. Vaccination and possibly revaccination, could be an important complement to ART in preventing further complications in this population4.
The impact of VPDs in HIV-infected individuals is not only related to the acute phase mortality, but also derives from the high prevalence of these diseases in the HIV population, with effects on long-term morbidity and mortality 5.
Vaccines enhance immunity against infections that may have been compromised following HIV infection. The benefits of vaccination in HIV-infected individuals must be weighed against its risks. However, in the absence of severe immunosuppression, the majority of routine vaccines, including live attenuated vaccines, have been found to be safe for use in HIV-infected individuals 2. At present the evidence suggests that vaccination of HIV-infected persons with suppressed viral loads and nadir CD4+ counts greater than 200 cells/µL have little or no deleterious effects on immune and inflammatory activation 4,6. The duration of seroprotection for most vaccines has been shown to be shorter in HIV-infected patients compared to uninfected persons 7. There are insufficient data to guide the optimal timing for revaccination or booster vaccination among HIV-infected persons 8.
There are no national guidelines for the use of vaccines for HIV-infected persons in South Africa. Establishment of guidelines could contribute to improving vaccine uptake in this population. The national guidelines will also help healthcare workers in decision making towards vaccinating HIV-infected individuals. The use of vaccines in HIV-infected persons is generally safe and causes no harm among patients with CD4+ counts above 200cells/µL uL and with very low viral load (< 50 copies/mL) 9,10. Even among HIV-infected individuals who are severely immunocompromised, the majority of non-live vaccines are potentially safe, although the immunogenicity and effectiveness need to be elucidated.
As part of a comprehensive approach to the management of HIV-infected individuals, the Southern African HIV Clinicians Society aims to promote the use of vaccines in this group. Currently, there are no guidelines on the use of vaccines among HIV-infected persons in South Africa. Furthermore, suboptimal knowledge among HIV-infected persons and healthcare providers undermines the use of vaccines in a population that could otherwise benefit most from vaccination.
CHALLENGE OF VACCINATIONS
Challenges faced by the healthcare providers wanting to vaccinate HIV-infected persons include a lack of national guidelines and policies. Secondly, vaccines are not generally available at settings where HIV-infected adults seek care.
Furthermore, cost of the vaccines may be a limiting factor in the health system which is already burdened by various other costs. These barriers impact negatively on the uptake of vaccines among HIV-infected adolescents and adults.
RATIONALE FOR THE DEVELOPMENT OF NATIONAL GUIDELINES
The epidemiology of HIV disease has changed significantly in the last 10 years in South Africa. More people with HIV are living longer as more people get access to ART. Associated with this increase in life expectancy is an increased risk of VPDs despite suppressive ART therapy.
SCOPE OF GUIDELINE
These national guidelines for vaccines available for HIV-infected adolescents and adults in South Africa have been developed to address challenges of adolescent and adult immunisation in the setting of endemic HIV/AIDS. The guidelines specifically focus on the most common VPDs in sub-Saharan Africa among HIV-infected adolescents and adults. The best available evidence has been used to make recommendations on the appropriate use of active and passive immunisation in HIV-infected adolescents and adults.