Are there differences in disease progression and mortality among male and female HIV patients on antiretroviral therapy? A meta-analysis of observational cohorts

Prevalence and predictors of viral load suppression in adults living with HIV in the western region of Ghana: A cross-sectional study

Background

Although antiretroviral therapy is beneficial and available free of cost to patients, several roadblocks still prevent patients from reaching viral suppression. This research aimed to determine the prevalence rate of viral suppression among people living with HIV in the western region of Ghana and identify the factors contributing to viral non-suppression.

Methods

A cross-sectional study was conducted on 7199 HIV-positive adults. All data from the Sekondi Public Health Laboratory database was exported to Microsoft Excel and then verified and filtered before being exported to STATA 16.1. Viral non-suppression was modeled statistically using logistic regression.

Results

Viral load suppression was achieved in 5465 (75.91%) study participants who received antiretroviral treatment. However, 1734 participants (24.0%) did not achieve viral suppression. Patients with poor adherence to ARV (AOR 0.30; 95% CI 0.16, 0.58) and fair adherence to ARV (AOR 0.23; 95% CI 0.12, 0.45) were associated with a lower odd of viral non-suppression. Patients with six (6) months to two (2) years of treatment before viral load testing (AOR 0.67; 95% CI 0.46, 0.98) were also associated with a lower likelihood of viral non-suppression.

Conclusions

The rate of non-suppression was high, and the suppression rate fell short of the UNAIDS target. Poor ARV adherence, fair ARV adherence, and a treatment duration of six (6) months to two (2) years before viral load testing appear to be obstacles to viral load suppression. The research findings seem to suggest that viral load testing supports viral non-suppression. Therefore, using viral load tests to monitor medication's effects on health can motivate patients to adhere to their prescribed medication regimen. More research is needed to determine whether viral load testing can improve adherence. Given the high rate of virologic failure, the study highlights the importance of identifying antiretroviral resistance patterns.

Retention in care among people living with HIV in the national antiretroviral therapy programme in Guinea: A retrospective cohort analysis

Few studies have investigated retention in HIV care in West Africa. We measured retention in antiretroviral therapy (ART) programmes among people living with HIV and re-engagement in care among those lost to follow up (LTFU) in Guinea and identified associated risk factors using survival analysis. Patient-level data were analysed from 73 ART sites. Treatment interruptions and LTFU were defined as missing a ART refill appointment by over 30 days and by over 90 days respectively. A total of 26,290 patients initiating ART between January 2018 and September 2020 were included in the analysis. The mean age at ART initiation was of 36.2 years, with women accounting for 67% of the cohort. Retention 12 months after ART initiation was 48.7% (95%CI 48.1-49.4%). The LTFU rate was 54.5 per 1000 person-months (95% CI 53.6-55.4), with the peak hazards of LTFU occurring after the first visit and decreasing steadily over time. In an adjusted analysis, the hazards of LTFU were higher among men compared to women (aHR = 1.10; 95%CI 1.08-1.12), being aged 13-25 years old versus older patients (aHR = 1.07; 95%CI = 1.03-1.13), and among those initating ART in smaller health facilities (aHR = 1.52; 95%CI 1.45-1.60). Among 14,683 patients with an LTFU event, 4,896 (33.3%) re-engaged in care, of whom 76% did so within six months from LTFU. The re-engagement rate was 27.1 per 1000 person-months (95%CI 26.3-27.9). Treatment interruptions were correlated with rainfall patterns and end of year mobility patterns. Rates of retention and re-engagement in care are very low in Guinea, undermining the effectiveness and durability of first-line ART regimens. Tracing interventions and differentiated service delivery of ART, including multi-month dispensing may improve care engagement, especially in rural areas. Further research should investigate social and health systems barriers to retention in care.

Continuity of Care is Associated with Higher Appointment Adherence Among HIV Patients in Low Clinician-to-Patient Ratio Facilities in Western Kenya

We sought to determine the relationship between continuity of care and adherence to clinic appointments among patients receiving HIV care in high vs. low clinician-to-patient (C:P) ratios facilities in western Kenya. This retrospective analysis included 12,751 patients receiving HIV care from the Academic Model Providing Access to Healthcare (AMPATH) program, between February 2016-2019. We used logistic regression analysis with generalized estimating equations to estimate the relationship between continuity of care (two consecutive visits with the same provider) and adherence to clinic appointments (within 7 days of a scheduled appointment) over time. Adjusting for covariates, patients in low C:P ratio facilities who had continuity of care, were more likely to be adherent to their appointments compared to those without continuity (adjusted odds ratio = 1.50; 95% confidence interval, 1.33-1.69). Continuity in HIV care may be a factor in clinical adherence among patients in low C:P ratio facilities and should therefore be promoted.

Analysis of the trend of mortality from HIV/AIDS according to sociodemographic characteristics in Brazil, 2000 to 2018

This investigation analyzed the trend of HIV/AIDS mortality by sociodemographic characteristics in the Brazilian states from 2000 to 2018. This is an ecological study of time-series of standardized rates of mortality from AIDS overall, by gender, age group, marital status, and ethnicity/skin color, employing the Prais-Winsten generalized linear model. The results showed that the states with the highest rates were Rio Grande do Sul, Rio de Janeiro, São Paulo, and Santa Catarina. The trend was increasing in the North and Northeast. Men had higher rates than women and the general population. The most advanced age groups showed a growing trend. The analysis by marital status showed higher and growing rates among the unmarried. Blacks had higher rates, except for Paraná, with a mainly increasing trend. Mortality due to HIV/AIDS had different trends by sociodemographic characteristics, with a need for preventive and care actions for men, adults, older adults, unmarried, and black people due to the change in the mortality profile.

Neighbourhood-level material deprivation and response to combination antiretroviral therapy in the Canadian Observational Cohort (CANOC): a longitudinal cohort study

BACKGROUND

Socioeconomic status has been associated with higher viral loads and lower CD4 cell counts among people living with HIV. The objective of this study was to evaluate the relation between neighbourhood-level material deprivation and immunologic and virologic response to combination antiretroviral therapy (ART) among people living with HIV in Canada.

METHODS

The Canadian Observational Cohort (CANOC) is a longitudinal cohort of people living with HIV, containing data from 2000-2016 from 5 Canadian provinces. We defined response to combination ART as positive if the CD4 cell count increased by 50 cells/mm³ (0.05 cells × 10⁹/L) or more (CD4+) and viral load decreased to 50 copies/mL or less (VL+) within 6 months of treatment initiation. We further categorized response to therapy as concordant positive (CD4+/VL+), concordant negative (CD4-/VL-) or discordant (CD4+/VL- or CD4-/VL+). We used adjusted multinomial logistic regression to quantify the relation between neighbourhood-level material deprivation and immunologic and virologic response.

RESULTS

This study included 8274 people living with HIV, of which 1754 (21.2%) lived in the most materially deprived neighbourhoods. Most individuals (62.2%) showed a concordant positive response to combination ART. After adjustment, living in the most materially deprived neighbourhoods was associated with a CD4-/VL+ discordant response (adjusted odds ratio [OR] 1.31, 95% confidence interval [CI] 1.06-1.62) and a concordant negative response (adjusted OR 1.45, 95% CI 1.13-1.86), using a concordant positive response as the reference. No other deprivation quartile was independently associated with a particular response.

INTERPRETATION

People living with HIV from the most materially deprived neighbourhoods had increased odds of poor immunologic or virologic response to combination ART. These results motivate further study of the specific socioeconomic factors that potentially affect response to combination ART among people living with HIV in Canada.

Development and external validation of a prognostic model for survival of people living with HIV/AIDS initiating antiretroviral therapy

Background: Most existing prognostic models for people living with HIV/AIDS (PLWHA) were derived from cohorts in high-income settings established a decade ago and may not be applicable for contemporary patients, especially for patients in developing settings. The aim of this study was to develop and externally validate a prognostic model for survival in PLWHA initiating ART based on a large population-based cohort in China.

Methods: We obtained data for patients from the Chinese National Free Antiretroviral Treatment Program database. The derivation cohort consisted of PLWHA treated between February 2004 and December 2019 in a tertiary center in Guangzhou, South China, and validation cohort of patients treated between February 2004 to December 2018 in another tertiary hospital in Shenyang, Northeast China. We included ART-naive patients aged above 16 who initiated a combination ART regimen containing at least three drugs and had at least one follow-up record. We assessed 20 candidate predictors including patient characteristics, disease characteristics, and laboratory tests for an endpoint of death from all causes. The prognostic model was developed from a multivariable cox regression model with predictors selected using the least absolute shrinkage and selection operator (Lasso). To assess the model's predictive ability, we quantified the discriminative power using the concordance (C) statistic and calibration accuracy by comparing predicted survival probabilities with observed survival probabilities estimated with the Kaplan–Meier method.

Findings: The derivation cohort included 16481 patients with a median follow-up of 3·41 years, among whom 735 died. The external validation cohort comprised 5751 participants with a median follow-up of 2·71 years, of whom 185 died. The final model included 10 predictors: age, body mass index, route of HIV acquisition, coinfection with tuberculosis, coinfection with hepatitis C virus, haemoglobin, CD4 cell count, platelet count, aspartate transaminase, and plasma glucose. The C-statistic was 0·84 (95% confidence interval 0·82–0·85) in internal validation after adjustment of optimism and 0·84 (0·82–0·87) in external validation, which remained consistently above 0·75 in all landmark time points within five years of follow up when using time-updated laboratory measurements. The calibration accuracy was satisfactory in both derivation and validation cohorts.

Interpretation: We have developed and externally validated a model to predict long-term survival in PLWHA on ART. This model could be applied to individualized patient counseling and management during treatment, and future innovative trial design.

Funding: Natural Science Foundation of China Excellent Young Scientists Fund, Natural Science Foundation of China International/Regional Research Collaboration Project, Natural Science Foundation of China Young Scientist Fund, the National Science and Technology Major Project of China,National Special Research Program of China for Important Infectious Diseases, 13th Five-Year Key Special Project of Ministry of Science and Technology, and the Joint-innovation Program in Healthcare for Special Scientific Research Projects of Guangzhou.

Mortality during tuberculosis treatment in South Africa using an 8-year analysis of the national tuberculosis treatment register

In 2011, the South African HIV treatment eligibility criteria were expanded to allow all tuberculosis (TB) patients lifelong ART. The impact of this change on TB mortality in South Africa is not known. We evaluated mortality in all adults (≥ 15 years old) treated for drug-susceptible TB in South Africa between 2009 and 2016. Using a Cox regression model, we quantified risk factors for mortality during TB treatment and present standardised mortality ratios (SMR) stratified by year, age, sex, and HIV status. During the study period, 8.6% (219,618/2,551,058) of adults on TB treatment died. Older age, male sex, previous TB treatment and HIV infection (with or without the use of ART) were associated with increased hazard of mortality. There was a 19% reduction in hazard of mortality amongst all TB patients between 2009 and 2016 (adjusted hazard ratio: 0.81 95%CI 0.80-0.83). The highest SMR was in 15-24-year-old women, more than double that of men (42.3 in 2016). Between 2009 and 2016, the SMR for HIV-positive TB patients increased, from 9.0 to 19.6 in women, and 7.0 to 10.6 in men. In South Africa, case fatality during TB treatment is decreasing and further interventions to address specific risk factors for TB mortality are required. Young women (15-24-year-olds) with TB experience a disproportionate burden of mortality and interventions targeting this age-group are needed.

Antiretroviral therapy in community pharmacies - Implementation and outcomes of a differentiated drug delivery model in Nigeria

INTRODUCTION

The World Health Organization recommended differentiated models of care portends opportunities to decongest hospitals providing antiretroviral therapy (ART) and improve retention, especially in developing countries. A community pharmacy-based ART refill model was implemented where stable clients were devolved to community pharmacies for routine refills at a service fee, to promote private sector participation and sustainability of ART services. The aim of this study was to assess the feasibility, acceptability and outcomes of this model in Nigeria.

METHODS

A population-based retrospective analysis of the community pharmacy ART refill program of the United States Agency for International Development-funded 'Strengthening Integrated Delivery of HIV/AIDS Services' project in Lagos, Rivers, Cross River and Akwa Ibom States from October 2016 to February 2018 was conducted. Standard descriptive statistical methods were used for baseline demographic and clinical characteristics of study participants. Outcomes were assessed using the Chi-square test and a multivariate logistic regressions model. Statistical significance was defined at α-level of 0.05. Analyses were performed using SPSS for Windows version 23 (IBM Corp, Armonk, USA).

RESULTS

A total of 10015 participants representing 14.4% of ART clients in 50 hospitals opted for this model and were devolved to 244 community pharmacies. All clients consented and paid a service fee of N1000 (about $3) per refill visit. Median follow-up duration was 6 months. Prescription refill rate was 95% (95% CI 94.2-95.3). Retention rate was 98% while viral suppression was 99.12%. Refill rates were significantly affected by ART duration, regimen, age and location (P < 0.001, 0.004, 0.034 and < 0.001 respectively).

CONCLUSIONS

This community pharmacy ART refill model of differentiated care is feasible and acceptable by clients and providers and demonstrated excellent clinical outcomes of retention and viral suppression. The ability and willingness of some clients to contribute financially to their HIV care was also demonstrated.

Sex differences in HIV treatment outcomes and adherence by exposure groups among adults in Guangdong, China: A retrospective observational cohort study

INTRODUCTION

We aimed to assess sex differences in treatment outcomes and adherence comparing men who have sex with women (MSW), men who have sex with men (MSM), and women who have sex with men (WSM), as well as men and women who inject drugs living with HIV on combination antiretroviral therapy (ART) in Guangdong, China.

METHODS

We performed a retrospective observational cohort study with data from the National Free Antiretroviral Treatment Program database. We included ART-naive patients aged 18 to 80 years who had contracted HIV through sex or injecting drugs, initiated first-line ART between January 2004 and December 2016, and had at least 60 days of follow-up. Participants were followed for five years. Kaplan-Meier analysis and Cox proportional hazard models were used to evaluate all-cause mortality. Cumulative incidence function and Cox proportional hazards models accounting for competing risks were used to evaluate disease progression to AIDS. Modified Poisson regression models were used to evaluate immunological and virological responses and loss to follow-up. Repeated measures analysis was used to evaluate regular CD4+ cell count, HIV viral load monitoring, ART adherence, side effects, and interruption of ART.

FINDINGS

We included 26,409 persons living with HIV. 21,779 (82·5%) people acquired HIV through sex (5118 WSM [23·5%], 8506 MSW [39·0%], 8175 MSM [37·5%]), and 4610 people (17·5%) through injection drug use (249 women [5·4%], 4361 men [94·6%]). Among those infected through sex, MSW had increased risks of all-cause mortality (adjusted hazard ratio [aHR] 1·48, 95% CI 1·20-1·83), progression to AIDS (1·27, 1·09-1·47), virological failure (adjusted incidence rates ratio [aIRR] 1·27, 95% CI 1·09-1·48), and loss to follow-up (1·22, 1·10-1·35) compared to WSM. In contrast, MSM had lower risk of all-cause mortality (aHR 0·49, 95%CI 0·32-0·76), disease progression to AIDS (0·83, 0·68-1·00), and virological failure (aIRR 0·78, 95%CI 0·65-0·94), were more likely to receive regular CD4+ cell count (1·08, 1·07-1·10) and HIV viral load monitoring (1·13, 1·12-1·15), were less likely to report missing ART doses (0·54, 0·49-0·61), interrupt ART (0·34, 0·26-0·44), or be lost to follow-up (0·56, 0·49-0·65) compared to WSM. Men who inject drugs were almost twice as likely as women who inject drugs to die (aHR 1·72, 95%CI 1·03-2·85), experience disease progression to AIDS (2·05, 1·18-3·57), virological failure (aIRR 1·81, 95%CI 1·19-2·76), report ART side effects (1·78, 1·43-2·22), and interruptions in ART (2·29, 1·50-3·50).

INTERPRETATION

Our findings highlight the importance of identifying potentially at-risk MSW and promoting HIV education and testing among them. Particular attention is warranted among men who inject drugs to improve timely HIV diagnosis, drug interaction management, and retention in treatment. Additional research from rural settings is needed to assess the long-term treatment outcomes and adherence in MSM with HIV.

Parental obligations, care and HIV treatment: How care for others motivates self-care in Zimbabwe

This article examines how parental obligations of care intersect with HIV treatment-seeking behaviours and retention. It draws on qualitative data from eastern Zimbabwe, produced from 65 interviews. Drawing on theories of practice and care ethics, our analysis revealed that norms of parental obligation and care acted as key motivators for ongoing engagement with HIV services and treatment. Parents' attentiveness to the future needs of their children (caring about), and sense of obligation (taking care of) and improved ability to care (caregiving) following treatment initiation, emerged as central to understanding their drive for self-care and engagement with HIV services.

Body and mind: retention in antiretroviral treatment care is improved by mental health training of care providers in Ethiopia

BACKGROUND

Ethiopia has achieved a high coverage of antiretroviral treatment (ART), but maintaining lifelong care is still a great challenge. Mental illnesses often co-exist with HIV/AIDS and may compromise the retention on ART. In order to improve prolonged retention in ART care, basic training in mental health care was introduced for ART providers, but this hasn't been evaluated yet. The aim of this study was to examine if this training has improved patient retention in care.

METHOD

A retrospective cohort study was employed to compare attrition from ART between clients attended by care provider trained with basic mental health service (exposed) and those in the standard ART follow-up care (unexposed) in public health facilities. A routine patient follow-up electronic database enrolled for ART between 2005 and 2017 was abstracted for the study. The Kaplan-Meier plot was used to compare the attrition rates between the two groups. The log-rank test was used to assess differences in the groups. The Cox proportional hazards regression model was used to determine predictors of attrition. We used estimated effect size of hazard ratios (HR) with 95% confidence intervals (CI).

RESULT

During the 12 years of observation, 8009 study participants under ART were followed for 33,498 person-years. The incidence of attrition was 6.5 per 100 person-years and 21% higher in the unexposed group (HR 1.21; 95% CI 1.1, 1.3), and retention in care was significantly higher in the mental health exposed group throughout the study period. WHO clinical staging III/IV, tuberculosis coinfection, the male gender, and poor functional status were independent risk factors for attrition.

CONCLUSION

We found that clients in the group exposed to mental health care training tended to have better retention in ART care with some variation according to gender, WHO Clinical stage and functional status. Training of ART providers in mental health may be considered in order to strengthen ART retention in low resource settings.

The impact of diabetes on CD4 recovery in persons with HIV in an urban clinic in the United States

The purpose of this study was to exam the impact of type 2 diabetes mellitus (T2DM) on CD4 cell count trends in adults with HIV. In a longitudinal retrospective study in an urban primary care HIV clinic in the southeastern United States from 2010 to 2012, patients with HIV medical charts were audited to obtain their CD4 cell count, diabetes status, weight, and demographic information. Rates of increase of CD4 T cell count (i.e. slopes) were obtained using a linear mixed-effects model. Most of the HIV-T2DM cohort (n = 262) and HIV-only cohort (n = 2399) were African American (76%) and male (77%). The CD4 T cell counts were consistently higher in the HIV-T2DM cohort ( p < .0001). The mean rate of CD4 T cell count increase (mean ± SE) was 63 ± 9 cells/µl/year in HIV-T2DM African American women and 28 ± 7 cells/µl/year in HIV-T2DM African American men ( p = 0.003). In the multivariable slope analysis, the CD4 T cell count increase was significantly faster for HIV-T2DM African American women than for all other patients (mean difference = 30/cells/µl/year, 95% CI: 13-47; p < 0.001). Gender, race/ethnicity, and the diagnosis of diabetes influenced the recovery of CD4 cell counts.

Sex disparities in outcomes among adults on long-term antiretroviral treatment in northern Nigeria

BACKGROUND

There are conflicting reports of sex differences in HIV treatment outcomes in Africa. We investigated sex disparities in treatment outcomes for adults on first line antiretroviral treatment (ART) in Nigeria.

METHODS

We compared clinical and immunologic responses to ART between HIV-infected men (n=205) and women (n=140) enrolled in an ART program between June 2004 and December 2007, with follow-up through June 2014. We employed Kaplan-Meier estimates to examine differences in time to immunologic failure and loss to follow-up (LTFU), and generalized estimating equations to assess changes in CD4+ count by sex.

RESULTS

Men had lower baseline mean CD4+ count compared to women (327.6 cells/µL vs 413.4, respectively, p<0.01). Women had significantly higher rates of increase in CD4+ count than men, even after adjusting for confounders, p<0.0001. There was no significant difference in LTFU by sex: LTFU rate was 2.47/1000 person-months (95% CI 1.6-3.9) in the first five years for men vs 1.98/1000 person-months (95% CI (1.3-3.0) for women. There was no difference in time to LTFU by sex over the study period.

CONCLUSIONS

Women achieved better long-term immune response to ART at baseline and during treatment, but had similar rates of long-term retention in care to men. Targeted efforts are needed to improve immune outcomes in men in our setting.

Visual analogue scale (VAS) measurement of antiretroviral adherence in people living with HIV (PLWH): a meta-analysis

Effective treatment of HIV hinges upon maintaining adequate antiretroviral therapy adherence. Accurate, cost-effective measurement of medication adherence is needed to best respond to the HIV pandemic. The visual analogue scale (VAS) appears to be a simple and easy to use measure of adherence but the current literature on its use is mixed. This meta-analysis (1) describes VAS concordance with other measures of medication adherence and viral load; and (2) examines how research methods moderate the reported strength of the VAS-viral load relationship. Literature searches were conducted electronically and by hand with a total of 20 studies included in the present study. The VAS showed large strength associations with most other measures of adherence and a smaller association with viral load. More rigorous methodological quality significantly improved the VAS-viral load effect size. We conclude with optimization recommendations for VAS use in clinical practice and research design.

B-cell development and pneumococcal immunity in vertically acquired HIV infection

OBJECTIVES

Many children with HIV infection now survive into adulthood. This study explored the impact of vertically acquired HIV in the era of antiretroviral therapy on the development of humoral immunity.

DESIGN

Natural and vaccine-related immunity to pneumococcus and B-cell phenotype was characterized and compared in three groups of young adults: those with vertically-acquired infection, those with horizontally acquired infection and healthy controls.

METHODS

Serotype-specific pneumococcal (Pnc) immunoglobulin M and G concentrations before and up to 1 year post-Pnc polysaccharide (Pneumovax) immunization were determined, and opsonophagocytic activity was analysed. B-cell subpopulations and dynamic markers of B-cell signalling, turnover and susceptibility to apoptosis were evaluated by flow cytometry.

RESULTS

HIV-infected patients showed impaired natural Pnc immunity and reduced humoral responses to immunization with Pneumovax; this was greatest in those viraemic at time of the study. Early-life viral control before the age of 10 years diminished these changes. Expanded populations of abnormally activated and immature B-cells were seen in both HIV-infected cohorts. Vertically infected patients were particularly vulnerable to reductions in marginal zone and switched memory populations. These aberrations were reduced in patients with early-life viral control.

CONCLUSION

In children with HIV, damage to B-cell memory populations and impaired natural and vaccine immunity to pneumococcus is evident in early adult life. Sustained viral control from early childhood may help to limit this effect and optimize humoral immunity in adult life.

Combined effect of sex and age in response to antiretroviral therapy in HIV-infected patients

BACKGROUND

Gender-specific data on the management of HIV infection are scarce. Further, an increase in the proportion of new HIV diagnoses in older persons has been observed. Using data from the CoRIS cohort, we compared immunovirological responses and survival in HIV-infected men and women who started their first combination antiretroviral therapy (cART) when aged < /≥50 years.

METHODS

We used multivariable logistic, linear and Cox regression, adjusting for potential confounders and including an interaction between age and sex, to assess differences in immunovirological responses and mortality, respectively.

RESULTS

At 96 weeks, among subjects <50 years, women were less likely than men to achieve virological response (VR; adjusted OR [aOR] 0.77, 95% CI 0.60, 0.99) and among women, older individuals were more likely to achieve VR than the younger ones (aOR 1.96; 95% CI 1.15, 3.34). Initiating cART at ≥50 years was associated with lower increases in CD4⁺ T-cell count both in men (-65.8; 95% CI -91.3, -40.3) and women (-37.7; 95% CI -79.7, 4.4) and women showed higher increases than men in both subjects aged <50 (21.8; 95% CI -1.9, 45.5) and ≥50 years at cART initiation (49.9; 95% CI 19.9, 79.9). A higher risk of death in men ≥50 was observed (adjusted hazard ratio [aHR] 2.69; 95% CI 1.73, 4.21), but not in women (aHR 1.49; 95% CI 0.70, 1.14). Women experienced lower mortality than men <50 (0.66; 95% CI 0.41, 1.07) and in those ≥50 (0.37; 95% CI 0.14, 0.93).

CONCLUSIONS

Sex and age at cART initiation have a noticeable association with both virological and immunological responses and mortality. Age ≥50 is associated with poorer immunological response and higher mortality but this effect is less pronounced in women than in men.