Care of Critically Ill Patients with Human Immunodeficiency Virus

Care of patients with human immunodeficiency virus (HIV) infection in the intensive care unit (ICU) has changed dramatically since the infection was first recognized in the United States in 1981. The purpose of this review is to describe the current important aspects of care of patients with HIV infection in the ICU, with a primary focus on the United States and developed countries. The epidemiology and initial approach to diagnosis and treatment of HIV (including the newest antiretroviral guidelines), common syndromes and their management in the ICU, and typical comorbidities and opportunistic infections of patients with HIV infection are discussed.

Discovery of anti-influenza nucleoside triphosphates targeting the catalytic site of A/PR/8/34/H1N1 polymerase

In an effort to develop potent anti-influenza drugs that inhibit the activity of influenza virus RNA-dependent RNA polymerase (IAV RdRp), a database of nucleoside triphosphates with ~800 molecules were docked with the homology model of IAV RdRp from A/PR/8/34/H1N1 strain. Out of top 12 molecules that bind with higher affinities to the catalytic site of IAV RdRp above and below the PB1 priming loop, only seven molecules decreased the transcriptional activity of the viral RNA polymerase with an IC₅₀ in the range of 0.09–3.58 µM. Molecular docking combining with experimental study indicated that the molecules with linear chain are more effective in inhibiting IAV RdRp replication than the molecules with V-shaped and are cyclic in nature. A correlation between ΔG and LogIC₅₀ for these seven compounds resulted an R² value of 0.73. Overall, these newly developed seven nucleoside triphosphates lay a strong foundation for the future development of a new therapeutics that can satisfy the Lipinski’s rule of five exhibiting high specificity to the catalytic site of influenza-A viruses.

Etiology, clinical, and epidemiological characteristics of severe respiratory infection in people living with HIV

People living with HIV (PLWH) are more prone to severe respiratory infections. We used the severe acute respiratory infection (SARI) definition to describe the etiology, clinical, and epidemiological characteristics in this population. This was a prospective observational study including PLWH hospitalized with fever and cough. Those with symptom onset up to 10 days were classified as severe acute respiratory infection and 11–30 days as non-severe acute respiratory infection. Blood, urine samples and nasopharyngeal swabs were collected. Data were extracted from patient charts during their hospital stay. Forty-nine patients were included, median CD4 cell count: 80 cells/mm³, median time since HIV diagnosis and hospital admission: 84 months and 80% were antiretroviral therapy exposed. Twenty-seven patients were classified as SARI. Etiology was identified in 69%, 47% were polymicrobial. Respiratory virus (9 SARI vs. 13 non-SARI), bacteria (5 SARI vs. 4 non-SARI), Mycobacterium tuberculosis (6 SARI group vs. 7 non-SARI group), Pneumocystis jirovecii (4 SARI vs. 1 non-SARI), Cryptococcus neoformans (1 SARI vs. 3 non-SARI), and influenza A (1 SARI vs. 2 non-SARI). Dyspnea was statistically more prevalent in SARI (78% vs. 36%, p = 0.011) but the risk of death was higher in the non-SARI (4% vs. 36%, p = 0.0067). In the severely immunocompromised PLWH, severe acute respiratory infection can be caused by multiple pathogens and codetection is a common feature.

Treating HIV-Positive/Non-AIDS Patients for Community-Acquired Pneumonia with ART

PURPOSE OF REVIEW

This article reviews the most recent publications on community-acquired pneumonia (CAP) in the HIV-infected population on antiretroviral therapy (ART), focusing on epidemiology, prognostic factors, etiology, and antimicrobial therapy. The data discussed here were mainly obtained from a non-systematic review using Medline and references from relevant articles.

RECENT FINDINGS

CAP remains a major cause of morbidity and mortality among HIV-infected patients and incurs high health costs despite the introduction of ART. HIV-infected patients are generally known to be more susceptible to bacterial pneumonia. Streptococcus pneumoniae is the most frequently reported pathogen in HIV-infected patients on ART, who present a higher rate of bacteremia than non-HIV-infected patients. Several studies have also examined microbial etiology and prognostic factors of CAP in HIV-infected patients on ART. Despite the high rate of bacterial pneumonia in these patients, mortality rates are not higher than in patients without HIV infection.

Community-acquired bacterial pneumonia in adult HIV-infected patients

INTRODUCTION

Despite active antiretroviral therapy (ART), community-acquired pneumonia (CAP) remains a major cause of morbidity and mortality among human immunodeficiency virus (HIV)-infected patients and incurs high health costs. Areas covered: This article reviews the most recent publications on bacterial CAP in the HIV-infected population, focusing on epidemiology, prognostic factors, microbial etiology, therapy, and prevention. The data discussed here were mainly obtained from a non-systematic review using Medline, and references from relevant articles. Expert commentary: HIV-infected patients are more susceptible to bacterial CAP. Although ART improves their immune response and has reduced CAP incidence, these patients continue to present increased risk of pneumonia in part because they show altered immunity and because immune activation persists. The risk of CAP in HIV-infected patients and the probability of polymicrobial or atypical infections are inversely associated with the CD4 cell count. Mortality in HIV-infected patients with CAP ranges from 6% to 15% but in well-controlled HIV-infected patients on ART the mortality is low and similar to that seen in HIV-negative individuals. Vaccination and smoking cessation are the two most important preventive strategies for bacterial CAP in well-controlled HIV-infected patients on ART.

Impact of HIV on the severity of influenza

Despite current antiretroviral therapy, HIV/AIDS is one of the most prelevant problems in healthcare worldwide. Similarly, influenza viruses are causes of epidemics outbreaks. HIV-infected patients are considered a high risk group for severe influenza infection, although several recent observational studies suggest that not all HIV-infected patients are equally susceptible to complications and that these patients should be stratified by their immunodeficiency status and other factors (such as smoking or comorbidities). Here, we have compiled the most recent data on the impact that HIV has on influenza infection.

Pandemic Influenza A (H1N1) Virus Infection Increases Apoptosis and HIV-1 Replication in HIV-1 Infected Jurkat Cells

Influenza virus infection has a significant impact on public health, since it is a major cause of morbidity and mortality. It is not well-known whether influenza virus infection affects cell death and human immunodeficiency virus (HIV)-1 replication in HIV-1-infected patients. Using a lymphoma cell line, Jurkat, we examined the in vitro effects of pandemic influenza A (H1N1) virus (pH1N1) infection on cell death and HIV-1 RNA production in infected cells. We found that pH1N1 infection increased apoptotic cell death through Fas and Bax-mediated pathways in HIV-1-infected Jurkat cells. Infection with pH1N1 virus could promote HIV-1 RNA production by activating host transcription factors including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), nuclear factor of activated T-cells (NFAT) and activator protein 1 (AP-1) through mitogen-activated protein kinases (MAPK) pathways and T-cell antigen receptor (TCR)-related pathways. The replication of HIV-1 latent infection could be reactivated by pH1N1 infection through TCR and apoptotic pathways. These data indicate that HIV-1 replication can be activated by pH1N1 virus in HIV-1-infected cells resulting in induction of cell death through apoptotic pathways.

Host genetics of severe influenza: from mouse Mx1 to human IRF7

Influenza viruses cause mild to moderate respiratory illness in most people, and only rarely devastating or fatal infections. The virulence factors encoded by viral genes can explain seasonal or geographic differences at the population level but are unlikely to account for inter-individual clinical variability. Inherited or acquired immunodeficiencies may thus underlie severe cases of influenza. The crucial role of host genes was first demonstrated by forward genetics in inbred mice, with the identification of interferon (IFN)-α/β-inducible Mx1 as a canonical influenza susceptibility gene. Reverse genetics has subsequently characterized the in vivo role of other mouse genes involved in IFN-α/β and -λ immunity. A series of in vitro studies with mouse and human cells have also refined the cell-intrinsic mechanisms of protection against influenza viruses. Population-based human genetic studies have not yet uncovered variants with a significant impact. Interestingly, human primary immunodeficiencies affecting T and B cells were also not found to predispose to severe influenza. Recently however, human IRF7 was shown to be essential for IFN-α/β- and IFN-λ-dependent protective immunity against primary influenza in vivo, as inferred from a patient with life-threatening influenza revealed to be IRF7-deficient by whole exome sequencing. Next generation sequencing of human exomes and genomes will facilitate the analysis of the human genetic determinism of severe influenza.

Determinants of vaccine immunogenicity in HIV-infected pregnant women: analysis of B and T cell responses to pandemic H1N1 monovalent vaccine

Influenza infections have high frequency and morbidity in HIV-infected pregnant women, underscoring the importance of vaccine-conferred protection. To identify the factors that determine vaccine immunogenicity in this group, we characterized the relationship of B- and T-cell responses to pandemic H1N1 (pH1N1) vaccine with HIV-associated immunologic and virologic characteristics. pH1N1 and seasonal-H1N1 (sH1N1) antibodies were measured in 119 HIV-infected pregnant women after two double-strength pH1N1 vaccine doses. pH1N1-IgG and IgA B-cell FluoroSpot, pH1N1- and sH1N1-interferon γ (IFNγ) and granzyme B (GrB) T-cell FluoroSpot, and flow cytometric characterization of B- and T-cell subsets were performed in 57 subjects. pH1N1-antibodies increased after vaccination, but less than previously described in healthy adults. pH1N1-IgG memory B cells (Bmem) increased, IFNγ-effector T-cells (Teff) decreased, and IgA Bmem and GrB Teff did not change. pH1N1-antibodies and Teff were significantly correlated with each other and with sH1N1-HAI and Teff, respectively, before and after vaccination. pH1N1-antibody responses to the vaccine significantly increased with high proportions of CD4+, low CD8+ and low CD8+HLADR+CD38+ activated (Tact) cells. pH1N1-IgG Bmem responses increased with high proportions of CD19+CD27+CD21- activated B cells (Bact), high CD8+CD39+ regulatory T cells (Treg), and low CD19+CD27-CD21- exhausted B cells (Bexhaust). IFNγ-Teff responses increased with low HIV plasma RNA, CD8+HLADR+CD38+ Tact, CD4+FoxP3+ Treg and CD19+IL10+ Breg. In conclusion, pre-existing antibody and Teff responses to sH1N1 were associated with increased responses to pH1N1 vaccination in HIV-infected pregnant women suggesting an important role for heterosubtypic immunologic memory. High CD4+% T cells were associated with increased, whereas high HIV replication, Tact and Bexhaust were associated with decreased vaccine immunogenicity. High Treg increased antibody responses but decreased Teff responses to the vaccine. The proportions of immature and transitional B cells did not affect the responses to vaccine. Increased Bact were associated with high Bmem responses to the vaccine.

HIV-1 and its gp120 inhibits the influenza A(H1N1)pdm09 life cycle in an IFITM3-dependent fashion

HIV-1-infected patients co-infected with A(H1N1)pdm09 surprisingly presented benign clinical outcome. The knowledge that HIV-1 changes the host homeostatic equilibrium, which may favor the patient resistance to some co-pathogens, prompted us to investigate whether HIV-1 infection could influence A(H1N1)pdm09 life cycle in vitro. We show here that exposure of A(H1N1)pdm09-infected epithelial cells to HIV-1 viral particles or its gp120 enhanced by 25% the IFITM3 content, resulting in a decrease in influenza replication. This event was dependent on toll-like receptor 2 and 4. Moreover, knockdown of IFITM3 prevented HIV-1 ability to inhibit A(H1N1)pdm09 replication. HIV-1 infection also increased IFITM3 levels in human primary macrophages by almost 100%. Consequently, the arrival of influenza ribonucleoproteins (RNPs) to nucleus of macrophages was inhibited, as evaluated by different approaches. Reduction of influenza RNPs entry into the nucleus tolled A(H1N1)pdm09 life cycle in macrophages earlier than usual, limiting influenza's ability to induce TNF-α. As judged by analysis of the influenza hemagglutin (HA) gene from in vitro experiments and from samples of HIV-1/A(H1N1)pdm09 co-infected individuals, the HIV-1-induced reduction of influenza replication resulted in delayed viral evolution. Our results may provide insights on the mechanisms that may have attenuated the clinical course of Influenza in HIV-1/A(H1N1)pdm09 co-infected patients during the recent influenza form 2009/2010.

Community-Acquired Pneumonia in HIV-Infected Individuals

Community-acquired pneumonia continues to be an important complication of HIV infection. Rates of pneumonia decrease with the use of antiretroviral therapy but continue to be higher than in HIV uninfected individuals. Risk factors for pneumonia include low blood CD4+ count, unsuppressed plasma HIV load, smoking, injection drug use and renal impairment. Immunization against Streptococcus pneumoniae and smoking cessation can reduce this risk. It is unclear whether newly reported viral respiratory pathogens (such as the Middle East respiratory syndrome coronavirus, will be more of a problem in HIV-infected individuals than the general population.

HIV virological suppression influences response to the AS03-adjuvanted monovalent pandemic influenza A H1N1 vaccine in HIV-infected children

Design

Children with HIV are especially susceptible to complications from influenza infection, and effective vaccines are central to reducing disease burden in this population. We undertook a prospective, observational study to investigate the safety and immunogenicity of the inactivated split-virion AS03-adjuvanted pandemic H1N1(2009) vaccine in children with HIV.

Setting

National referral centre for Paediatric HIV in Ireland.

Sample

Twenty four children with HIV were recruited consecutively and received two doses of the vaccine. The serological response was measured before each vaccine dose (Day 0 and Day 28) and 2 months after the booster dose. Antibody titres were measured using a haemagglutination inhibition (HAI) assay. Seroprotection was defined as a HAI titre ≥ 1:40; seroconversion was defined as a ≥ fourfold increase in antibody titre and a postvaccination titre ≥ 1:40.

Main outcome measures

The seroconversion rates after prime and booster doses were 75% and 71%, respectively. HIV virological suppression at the time of immunization was associated with a significantly increased seroconversion rate (P = 0·009), magnitude of serological response (P = 0·02) and presence of seroprotective HAI titres (P = 0·017) two months after the booster dose. No other factor was significantly associated with the seroconversion/seroprotection rate. No serious adverse effects were reported. Vaccination had no impact on HIV disease progression. The AS03-adjuvanted pandemic H1N1 vaccine appears to be safe and immunogenic among HIV-infected children. A robust serological response appears to be optimized by adherence to a HAART regimen delivering virological suppression.

Influenza vaccination in immunocompromised patients: efficacy and safety

Yearly administration of the influenza vaccine is the main strategy to prevent influenza in immunocompromised patients. Here, we reviewed the recent literature regarding the clinical significance of the influenza virus infection, as well as the immunogenicity and safety of the influenza vaccine in HIV‑infected individuals, solid-organ and stem-cell transplant recipients and patients receiving biological agents. Epidemiological data produced during the 2009 influenza pandemic have confirmed that immunocompromised patients remain at high risk of influenza-associated complications, namely viral and bacterial pneumonia, hospitalization and even death. The immunogenicity of the influenza vaccine is overall reduced in immunocompromised patients, although a significant clinical protection from influenza is expected to be obtained with vaccination. Influenza vaccination is safe in immunocompromised patients. The efficacy of novel strategies to improve the immunogenicity to the vaccine, such as the use of adjuvanted vaccines, boosting doses and intradermal vaccination, needs to be validated in appropriately powered clinical trials.

The impact of influenza A(H1N1)pdm09 infection on immunosuppressed patients

Before the advent of the influenza A(H1N1)pdm virus in 2009, the information available about the clinical manifestations and prognosis of influenza in immunosuppressed patients was scarce. With the 2009 pandemic, knowledge of the behavior, severity and importance of antiviral therapy for influenza A infection in immunocompromised hosts has increased considerably. The aim of the present manuscript is to review the main challenges of influenza in the most representative immunosuppressed populations such as solid organ transplant recipients, hematopoietic stem cell transplant recipients, patients with solid and hematological cancer and human immunodeficiency virus infected patients.

Immune response after one or two doses of pandemic influenza A (H1N1) monovalent, AS03-adjuvanted vaccine in HIV infected adults

INTRODUCTION

Continued research is needed to evaluate and improve the immunogenicity of influenza vaccines in HIV infected patients. We aimed to determine the antibody responses after one or two doses of the AS03-adjuvanted pandemic influenza A (H1N1) vaccine in HIV infected patients.

METHOD

Following the influenza season 2009/2010, 219 HIV infected patients were included and divided into three groups depending on whether they received none (n=60), one (n=31) or two (n=128) doses of pandemic influenza A (H1N1) vaccine. At inclusion, antibody titers for all patients were analyzed and compared to pre-pandemic antibody titers analyzed from serum samples in a local storage facility.

RESULTS

4-9 months after a single immunization, we found a seroprotection rate of 77.4% and seroconversion rate of 67.7%. After two immunizations the rates increased significantly to seroprotection rate of 97.7% and seroconversion rate of 86.7%.

CONCLUSION

A single dose of AS03-adjuvanted pandemic influenza A (H1N1) vaccine created an adequate immune response in HIV infected patients lasting as long as 4-9 months. Two doses improved the immunogenicity further.

Higher memory responses in HIV-infected and kidney transplanted patients than in healthy subjects following priming with the pandemic vaccine

Background

Memory responses require immune competence. We assessed the influence of priming with AS03-adjuvanted pandemic vaccine (Pandemrix®) on memory responses of HIV patients, kidney recipients (SOT) and healthy controls (HC).

Method

Participants (HIV: 197, SOT: 53; HC: 156) were enrolled in a prospective study and 390/406 (96%) completed it. All had been primed in 2009/2010 with 1 (HC) or 2 (patients) doses of Pandemrix®, and were boosted with the 2010/2011 seasonal influenza vaccine. Geometric mean titres and seroprotection rates were measured 12 months after priming and 4 weeks after boosting. Primary and memory responses were directly compared in 191 participants (HCW: 69, HIV: 71, SOT: 51) followed during 2 consecutive seasons.

Results

Most participants (HC: 77.8%, HIV: 77.6%, SOT: 66%) remained seroprotected at 12 months post-priming. Persisting A/09/H1N1 titers were high in HIV (100.2) and HC (120.1), but lower in SOT (61.4) patients. Memory responses reached higher titers in HIV (507.8) than in HC (253.5) and SOT (136.9) patients. Increasing age and lack of HAART reduced persisting and memory responses, mainly influenced by residual antibody titers. Comparing 2009/2010 and 2010/2011 titers in 191 participants followed for 2 seasons indicated lower post-2010/2011 titers in HC (240.2 vs 313.9), but higher titers in HIV (435.7 vs 338.0) and SOT (136 vs 90.3) patients.

Conclusions

Priming with 2 doses of Pandemrix® elicited persistent antibody responses and even stronger memory responses to non-adjuvanted seasonal vaccine in HIV patients than 1 dose in healthy subjects. Adjuvanted influenza vaccines may improve memory responses of immunocompromised patients.

Trial Registration

ClinicalTrials.gov NCT01022905

Strong serological responses and HIV RNA increase following AS03-adjuvanted pandemic immunization in HIV-infected patients

INTRODUCTION

We aimed to determine the antibody responses and effect on viral load of the AS03-adjuvanted pandemic H1N1 vaccine in HIV-infected patients.

METHOD

A total of 121 HIV-infected patients and 138 healthy subjects were enrolled in a prospective, open-label study. Healthy subjects received one dose and HIV-infected patients two doses of the AS03-adjuvanted split influenza A/09/H1N1 vaccine (Pandemrix®; GlaxoSmithKline, Brentford, United Kingdom.) at an interval of 3-4 weeks. The study was extended in 2010/2011 for 66 patients. Geometric mean titres (GMTs), seroprotection rates (post-vaccination titre ≥ 1:40) and HIV-1 RNA levels were measured before and 4 weeks after immunization.

RESULTS

After two immunizations, the seroprotection rate (94.2 vs. 87%, respectively) and GMT (376 vs. 340, respectively) in HIV-infected patients were as high as in healthy subjects after one dose, regardless of CD4 cell count. Four weeks after immunization, HIV RNA was detected in plasma samples from 40 of 68 (58.0%) previously aviraemic patients [median 152 HIV-1 RNA copies/mL; interquartile range (IQR) 87-509 copies/mL]. Subsequent measures indicated that HIV RNA levels had again declined to <20 copies/mL in most patients (27 of 34; 79.4%). Following (nonadjuvanted) influenza immunization in 2010/2011, HIV RNA levels only slightly increased (median final level 28 copies/mL) in three of 66 (4.5%) previously aviraemic patients, including two of 25 (8%) patients in whom an increase had been elicited by AS03-adjuvanted vaccine the year before.

CONCLUSION

Most HIV-infected patients developed seroprotection after two doses of AS03-adjuvanted pandemic vaccine. A transient effect on HIV RNA levels was observed in previously aviraemic patients. A booster dose of the nonadjuvanted influenza vaccine containing the A/09/H1N1 strain the following year did not reproduce this finding, indicating a non-antigen-specific adjuvant effect.

Outcomes in HIV-infected patients admitted due to pandemic influenza

PURPOSE

To determine the clinical, epidemiological and prognostic factors of HIV-infected patients with influenza A H1N1 admitted to hospital.

METHODS

The study population was HIV infected patients with confirmed influenza infection admitted to hospital in a multicenter cohort. We analyzed demographic data, comorbid conditions, severe events (bronchopneumonia, respiratory insufficiency, respiratory distress, sepsis, admission to intensive care unit, death) and outcome. Data were analyzed using descriptive statistics. Proportions were compared using the χ(2) test or Fisher exact test, when applicable. Quantitative variables were compared using the Student t test or Mann-Whitney test. Prognostic impact was analyzed using logistic regression.

RESULTS

A total of 43 patients, of whom 62.8% were male, were included from 22 hospitals. The mean age was 43.3 years (interquartile range [IQR], 38.4-48.4). HIV was diagnosed for a mean of 14.5 years (IQR, 8.4-20.3). CD4 lymphocyte was <200 cells/μL in 38%; 85.7% were on antiretroviral therapy, and 66.7% virologically suppressed. Comorbid conditions were hepatitis B or C (74.4%), smoking (67.4%), chronic obstructive pulmonary disease (30.2%), asthma (14%), and obesity (8.6%). Seven patients had received seasonal influenza vaccination, and 2 the H1N1 vaccine. Cough (100%), fever (93%), gastrointestinal disorders (27.9%) or general--myalgia, general malaise--(67.4%) were the presenting symptoms. These were severe in 24 (55.8%) with 7 (16.3%) requiring intensive care. Two patients died. A lower CD4 lymphocyte count was associated with bacterial infection (P=.063) and longer hospital stay (P=.007). Early oseltamivir reduced severe cases (OR, 4.5; 1.1-18.3; P=.035).

CONCLUSIONS

HIV-infected patients admitted to hospital due to influenza A H1N1 had severe morbidity. Low CD4 lymphocytes correlated with longer hospitalization and bacterial infections. Early oseltamivir treatment reduced severe symptoms.

Pandemic H1N12009 influenza and HIV: a review of natural history, management and vaccine immunogenicity

PURPOSE OF REVIEW

The 2009 pandemic HIN1 influenza strain (H1N12009) produced more severe disease and increased risk for mortality. As an at-risk population for more severe influenza illness, particular concern regarding HIV patients triggered a focused effort to evaluate disease burden and vaccine efficacy in these populations.

RECENT FINDINGS

As with other immune-compromised individuals, most HIV-infected individuals recovered without major consequence. Although HIV infection was assumed to be a risk factor for more severe disease and death, the published literature does not indicate this to be so. Neuraminadase inhibitors were well tolerated by this population and there was no evidence of clinically significant pharmacokinetic interactions with antiretroviral therapy. Immunogenicity was increased with H1N12009 vaccine compared to the historical results of nonpandemic vaccines and optimized by the use of adjuvants. Booster dosing was also of benefit. H1N12009 vaccine was generally well tolerated without evidence of detrimental effect on HIV status.

SUMMARY

The worse case scenario was not realized for H1N12009 in the general population or in those with HIV. Immunization with adjuvant represents a key measure to protect this population from H1N12009 and other future novel influenza strains.

Updating our understanding of pulmonary disease associated with HIV infection

The introduction of highly active antiretroviral therapy (HAART) has resulted in a reduction of opportunistic infections associated with cellular and humoral immunosuppression. However, what is still unclear is the impact of HAART on the development of other diseases not associated with AIDS, such as lung cancer and COPD. The aim of this paper is to review the most innovative and relevant aspects of lung pathology in patients infected with HIV.

Influenza and HIV: lessons from the 2009 H1N1 influenza pandemic

Influenza is a common respiratory disease in adults, including those infected with HIV. In the spring of 2009, a pandemic influenza A (H1N1) virus (pH1N1) emerged. In this article, we review the existing literature regarding pH1N1 virus infection in HIV-infected adults, which suggests that susceptibility to pH1N1 virus infection and severity of influenza illness are likely not increased in HIV-infected adults without advanced immunosuppression or comorbid conditions. The risk of influenza-related complications, however, may be increased in those with advanced immunosuppression or high-risk comorbid conditions. Prevention and treatment of high-risk comorbid conditions and annual influenza vaccination should continue to be part of HIV clinical care to help prevent influenza illness and complications. Additional information about pH1N1 vaccine immunogenicity and efficacy in HIV-infected patients would be useful to guide strategies to prevent influenza virus infection in this population.

Influenza in immunocompromised patients: considerations for therapy

Influenza infection results in substantial morbidity and mortality in immunocompromised patients, and the risks for influenza and its related complications depend on the degree of immunosuppression. In addition to influenza vaccination and infection control precautions, two classes of antiviral drugs are currently approved for treatment and prophylaxis in uncomplicated infected patients. However, there are no randomized controlled trials assessing the efficacy and safety of licensed antivirals for influenza management in immunocompromised patients. The purpose of this article is to highlight some considerations for therapy in immunocompromised patients, the usefulness of vaccination for the prevention of influenza and the clinical interest in surveillance of antiviral resistance.