Safety of licensed vaccines in HIV-infected persons: a systematic review protocol

Management care improvement of people living with HIV: definition of a targeted clinical pathway in a University Hospital of South Italy

BACKGROUND AND AIM

In the world 37,9 billions live with Human Immunodeficiency Virus and, despite the availability of retroviral therapy, they have an higher risk to acquire other infectious diseases and to develop severe complications. According to several guidelines their immunization is crucial but only some center have developed a specific scheduled pathway and vaccination coverage is very low.  Aim of this study is: a)incentivize the active and free of charge offer of vaccines and increase of immunization coverage; b) application and implementation of a shared clinical pathway avoiding reluctance, embarrassment or shame by patients for their condition; d) instauration of an empathic relationship between doctor and patient; e) evaluation of side effects.

METHODS

A prospective study was conducted from October 2019 to February 2020 at the University Hospital G. Martino of Messina. Inclusion criteria were: age over 18; absence of other diseases; absence of immunization against HBV or HAV; CD4 count for live attenuated viral vaccines of 350/uL and for other vaccine 200/uL. A specific scheduled pathway was adopted for every patient. Statistical analysis was performed with Excel software.

RESULTS

86 patients were enrolled (74.4% were males, 79.1% were Italian; mean age=4013.3 SD).  An increase in administration was observed between 2018 and 2019 (+164.3% for flu and for other vaccines +370%).  The higher increase was observed for HPV one. No-one received DTpa, MMRV or Zoster vaccine.

CONCLUSIONS

The undertook clinical pathway showed the relevance of specific management of these patients and the need to increase the vaccination offer.

Herd Immunity to Ebolaviruses Is Not a Realistic Target for Current Vaccination Strategies

The recent West African Ebola virus pandemic, which affected >28,000 individuals increased interest in anti-Ebolavirus vaccination programs. Here, we systematically analyzed the requirements for a prophylactic vaccination program based on the basic reproductive number (R₀, i.e., the number of secondary cases that result from an individual infection). Published R₀ values were determined by systematic literature research and ranged from 0.37 to 20. R₀s ≥ 4 realistically reflected the critical early outbreak phases and superspreading events. Based on the R₀, the herd immunity threshold (I_c) was calculated using the equation I_c = 1 - (1/R₀). The critical vaccination coverage (V_c) needed to provide herd immunity was determined by including the vaccine effectiveness (E) using the equation V_c = I_c/E. At an R₀ of 4, the I_c is 75% and at an E of 90%, more than 80% of a population need to be vaccinated to establish herd immunity. Such vaccination rates are currently unrealistic because of resistance against vaccinations, financial/logistical challenges, and a lack of vaccines that provide long-term protection against all human-pathogenic Ebolaviruses. Hence, outbreak management will for the foreseeable future depend on surveillance and case isolation. Clinical vaccine candidates are only available for Ebola viruses. Their use will need to be focused on health-care workers, potentially in combination with ring vaccination approaches.