Efficacy and clinical effectiveness of influenza vaccines in HIV-infected individuals: a meta-analysis

Meta-analytical studies on the epidemiology, prevention, and treatment of human immunodeficiency virus infection

Since the beginning of the epidemic, extensive research has been conducted in the field of HIV infection. Original research and subsequent meta-analyses have contributed to a better understanding of the disease. Epidemiologic research has shown, for example, that male circumcision reduces the risk of female-to-male transmission. Nevertheless, the question whether circumcision confers protection against HIV transmission in MSM remains open. Studies have shown a positive correlation between HIV and HSV-2 infection. However, a recent RCT found that suppressive antiherpes therapy did not affect rates of HIV acquisition. Meta-analytical studies have advanced the knowledge on the global prevalence of infection among MSM, and disparities among black and white MSM. They have also solidified the evidence that the prophylactic use of ARVs reduces the risk of MTCT. It has also been shown that prolonged ruptured of membranes increases the rates of vertical transmission, and that breastfeeding is associated with postnatal transmission. In addition, prognostic markers of disease progression have been identified. The introduction of ART has resulted in substantial improvements in morbidity and mortality for HIV-seropositive individuals. Several studies have defined recommended and alternative regimens. In a recent meta-analysis it was shown that in treatment naïve patients, NNRTI-based or boosted-PI-based regimens are superior to triple NRTI or unboosted PI-based regimens in terms of virologic suppression. Recent evidence has demonstrated that ART can be successfully used in Africa with better outcomes in those receiving free treatment. Regarding resistance testing in treatment-experienced patients with virologic failure, GRT offers a benefit of small magnitude and there is insufficient evidence to support the use of PRT, in contrast to current guidelines. Meta-analyses have also shown that interventions to improve adherence can be successfully implemented. Finally, the efficacy of the influenza and hepatitis vaccine in the setting of HIV infection has been analyzed. As our knowledge advances, further questions will inevitably arise and will need to be addressed in well-conducted trials.

[Effects of influenza vaccination on the percentage of CD4+ T lymphocytes in HIV 1/2 positive patients: a cohort study]

OBJECTIVE

To determine the incidence of immunologic change in the percentage of CD4+ T lymphocytes in HIV 1/2 positive patients in the first quarter after influenza vaccination (P-CIR) and to compare the demographic and clinical characteristics associated with this change.

METHODS

We studied 105 patients with HIV/AIDS in a retrospective hospital cohort between 2001-2006. P-CIR was considered as a decrease of >3% in the prevaccination CD4+ percentage. Crude and adjusted OR (sex, age, antiretroviral therapy, clinical stability, prevaccination viremia and prevaccination total CD4) were evaluated by logistic regression (95%CI).

RESULTS

The incidence of P-CIR was 33.3%. P-CIR was persistent in 31.4% for 7 months after vaccination regardless of high prevaccination viremia. No association was found between demographic and clinical variables and P-CIR [crude OR: 0.90 (0.17-4.8); adjusted OR: 1.09 (0.17-6.8)].

CONCLUSIONS

The results showed that the immunological change after vaccination was not inconsiderable. However, this change was mainly transient.

Immunization in patients with HIV infection: are practical recommendations possible?

The purpose of this article is to review immunization recommendations for HIV-infected individuals in resource-constrained countries, particularly in sub-Saharan Africa. Recent evidence suggests that HIV-infected children are at risk for low immunization coverage in sub-Saharan Africa. Routine immunization is recommended for these children. In comparison with immunocompetent children, recommendations for live-attenuated vaccines differ in HIV-infected children. However, limited laboratory capacity to diagnose HIV infection amongst young children prevents the implementation of these HIV-specific guidelines in resource-constrained countries. Re-immunization has been the focus of recent research in high- and middle-income countries. Findings show that children established on highly active antiretroviral therapy have suboptimal vaccine-specific immunity and may benefit from re-immunization. Before re-immunization guidelines can be formulated for resource-constrained countries, several questions should be addressed, including whether all HIV-infected children will benefit from routine re-immunization and what optimal number of vaccine doses should be administered. Pneumococcal and influenza infections are important causes of morbidity and mortality amongst HIV-infected individuals. There is compelling evidence showing that pneumococcal conjugate vaccines will protect HIV-infected and uninfected children against invasive infection. Pneumococcal conjugate vaccines should be prioritized for introduction in countries with high HIV prevalence. Although, annual influenza immunization is recommended for HIV-infected individuals, the effectiveness in Africa remains unclear. In conclusion, this brief overview has identified several limitations of current immunization policy and practice for HIV-infected individuals living in resource-constrained countries.

Vaccination in Brazilian HIV-infected adults: a cross-sectional study

HIV-infected patients are at risk for vaccine-preventable infections. The Brazilian National Immunization Program provided recommendations for this population. However, the vaccine coverage reached by this program is unknown. This study aimed at evaluating the vaccine coverage of HIV-infected adults followed at Hospital das Clínicas, University of São Paulo School of Medicine. Data were collected on age, gender, mode of HIV transmission, Centers for Disease Classification 1993 classification (CDC/93), antiretrovirals, CD4 count, HIV viral load, and immunization charts, from April 2003 to August 2004. We interviewed 144 randomly selected patients, 74% male; mean age, 39.95 years; CDC classification: A, 40.6%; B, 19.6%; and C, 39.9%. Most of patients were undergoing highly active antiretroviral therapy (HAART; 86.8%). Mean CD4 count 442.6 cells/mm3. Viral load less than 400 copies per milliliter in 59.4% of patients. Only 36.1% of patients were adequately immunized for diphtheria/tetanus, 54.9% for pneumococcus, 24.3% for flu, and 76.9% for hepatitis B. In relation to live attenuated vaccines, 5 patients received measles, mumps, and rubella vaccine and 7 patients yellow fever vaccine. Two patients were vaccinated against yellow fever despite CD4 less than 200 cell/mm3. We verified poor vaccine coverage in HIV-infected patients. Vaccination campaigns and incorporation of vaccine rooms in sexually transmitted disease (STD)/AIDS clinics could improve this situation.

Influenzavirus infection is a primary cause of febrile respiratory illness in HIV-infected adults, despite vaccination

BACKGROUND

There are, to our knowledge, no prospective studies of respiratory tract infections in human immunodeficiency virus (HIV)-infected adults in the highly active antiretroviral therapy (HAART) era. We performed a surveillance study of outpatients who presented with fever and respiratory symptoms to examine the role of viral pathogens in these patients.

METHODS

Consecutive patients with a temperature of >38.0 degrees C and respiratory symptoms were recruited from a tertiary care HIV clinic during the period 2003-2006. Nasal pharyngeal samples were tested for influenzavirus A and B, respiratory syncytial virus, and human metapneumovirus using real-time multiplex polymerase chain reaction assays. Paired acute- and convalescent-phase serum samples were tested for respiratory viruses by complement fixation.

RESULTS

Fifty patients (90% of whom were receiving HAART) were included in the study (median CD4(+) T cell count, 325 cells/microL; median HIV RNA level, <50 copies/mL). A causative pathogen was identified in 25 patients (50%). Even though 76% of subjects had received influenza vaccine, viral infections were diagnosed in 21 patients (42%), as follows: influenza A, 10 patients; influenza B, 10; and parainfluenza virus type 3 infection, 1. Patients with and those without viral infection had similar demographic characteristics and HIV statuses. No patients with influenza and 23% of patients with other conditions had radiography-confirmed pneumonia (P=.07). Antibiotic prescriptions were common: 70% of patients received antibiotics. No patients with influenza required hospitalization, compared with 21% of other patients (P=.03).

CONCLUSIONS

Although illness was mild, influenza accounted for a large proportion of unscheduled visits to a health care provider for respiratory illness and was associated with unnecessary antibiotic prescriptions that may contribute to antimicrobial resistance. Vaccination alone was insufficient to prevent infection. Thus, specific identification and management of influenza should be performed in HIV-infected outpatients who present with fever and respiratory symptoms.