T cell anergy and activation are associated with suboptimal humoral responses to measles revaccination in HIV-infected children on anti-retroviral therapy in Nairobi, Kenya

Immunogenicity, effectiveness, and safety of SARS-CoV-2 vaccination in people with HIV

OBJECTIVES

People with HIV (PWH) experience a greater risk of morbidity and mortality following COVID-19 infection, and poorer immunological responses to several vaccines. We explored existing evidence regarding the immunogenicity, effectiveness, and safety of SARS-CoV-2 vaccines in PWH compared with controls.

METHODS

We conducted a systematic search of electronic databases from January 2020 until June 2022, in addition to conference databases, to identify studies comparing clinical, immunogenicity, and safety in PWH and controls. We compared results between those with low (<350 cells/μl) and high (>350 cells/μl) CD4 + T-cell counts where possible. We performed a meta-analysis of seroconversion and neutralization responses to calculate a pooled risk ratio as the measure of effect.

RESULTS

We identified 30 studies, including four reporting clinical effectiveness, 27 immunogenicity, and 12 reporting safety outcomes. PWH were 3% [risk ratio 0.97, 95% confidence interval (95% CI) 0.95-0.99] less likely to seroconvert and 5% less likely to demonstrate neutralization responses (risk ratio 0.95, 95% CI 0.91-0.99) following a primary vaccine schedule. Having a CD4 + T-cell count less than 350 cells/μl (risk ratio 0.91, 95% CI 0.83-0.99) compared with a CD4 + T-cell count more than 350 cells/μl, and receipt of a non-mRNA vaccine in PWH compared with controls (risk ratio 0.86, 95% CI 0.77-0.96) were associated with reduced seroconversion. Two studies reported worse clinical outcomes in PWH.

CONCLUSION

Although vaccines appear well tolerated in PWH, this group experience poorer immunological responses following vaccination than controls, particularly with non-mRNA vaccines and low CD4 + T-cell counts. PWH should be prioritized for mRNA COVID-19 vaccines, especially PWH with more advanced immunodeficiency.

Characteristics of refined lymphocyte subsets changes in people living with HIV/AIDS during antiretroviral therapy period: An observation from Wuhan, China

Background

To analyze the changing characteristics of continuous monitoring of refined lymphocyte subsets in people living with HIV/AIDS (PLWHA) during ART period.

Methods

Refined lymphocyte subsets was continuously monitored using flow cytometry for 173 PLWHA, who were hospitalized in Zhongnan Hospital of Wuhan University from August 17, 2021 to September 14, 2022. The effect of ART status and duration of ART on changes of refined lymphocyte subsets were compared in different groups. Then, the levels of refined lymphocyte subsets in PLWHA treated for more than 10 years were compared to those of 1086 healthy individuals.

Results

In addition to conventional CD4⁺ T lymphocytes and CD4⁺/CD8⁺ ratio, gradually increasing in numbers of CD3⁺CD4⁺CD45RO cells, CD3⁺CD4⁺CD45RA cells, CD45RA⁺CD3⁺CD4⁺CD25⁺CD127^low and CD45RO⁺CD3⁺CD4⁺CD25⁺CD127^low cells were found with the increase of ART duration. The number of CD4⁺CD28⁺ cells and CD8⁺CD28⁺ cells were 174/ul and 233/ul at 6 months post-ART, which gradually increased to 616/ul and 461/ul after ART initiation more than 10 years. Moreover, in ART ≤ 6 months, 6 months-3years, 3-10 years and >10 years groups, the percentage of CD3⁺CD8⁺HLA^-DR⁺/CD8 were 79.66%, 69.73%, 60.19% and 57.90%, respectively, and the differences between groups showed statistical significance (F=5.727, P=0.001). For those PLWHA with ART more than 10 years, the levels of CD4⁺ T lymphocytes, CD3⁺CD4⁺CD45RO cells, CD3⁺CD4⁺CD45RA cells, CD4⁺CD28⁺ cells and CD8⁺CD28⁺ cells can increase to levels similar to those of healthy control. However, for those PLWHA with ART more than 10 years, CD4⁺/CD8⁺ ratio was 0.86 ± 0.47, which was lower than that of healthy control (0.86 ± 0.47 vs 1.32 ± 0.59, t=3.611, P=0.003); absolute counts and percentage of CD3⁺CD8⁺HLA^-DR⁺ cells were 547/ul and 57.90%, which were higher than those of healthy control(547/ul vs 135/ul, t=3.612, P=0.003; 57.90% vs 22.38%, t=6.959, P<0.001).

Conclusion

Persistent ART can gradually improve the immune status of PLWHA, which is manifested in the increase of lymphocytes, function recovery of lymphocytes and reduction of aberrant activation status of the immune system. After 10 years of standardized ART, most lymphocytes could return to levels of healthy persons, although it may take longer to complete recovery for CD4⁺/CD8⁺ ratio and CD3⁺CD8⁺HLA^-DR⁺ cells.

COVID-19 Outcomes and Risk Factors Among People Living with HIV

Purpose of Review

In this review, we examine the intersection of the HIV and COVID-19 epidemics with focus on COVID-19-related health outcomes and risk factors for SARS-CoV-2 among people living with HIV (PLWH).

Recent Findings

Evidence to date do not suggest a higher incidence of SARS-CoV-2 infection among PLWH compared to the general population, although—once exposed—PLWH are at greater risk of severe COVID-19 outcomes. Key risk factors for severe COVID-19 include non-HIV comorbidities known to be associated with severe disease, as well as HIV-specific risk factors such as low CD4 + T-cell count, unsuppressed viral load, and tuberculosis co-infection. The disproportionate impact of the SARS-CoV-2 pandemic among Black, Latinx, and Native American/Alaskan Native PLWH could worsen pre-existing disparities in health outcomes among PLWH. Data on SARS-CoV-2 vaccine protection among PLWH needs additional study, although some studies suggest decreased humoral responses among those with low CD4 + T-cell counts, while there is a signal of increased vaccine breakthrough rates among PLWH in two large observational cohorts. Data on post-acute sequelae of SARS-CoV-2 (PASC) among PLWH is also limited.

Summary

PLWH do not have a higher susceptibility to SARS-CoV-2, but once exposed, they are at higher risk of severe COVID-19 outcomes. Additional resources will need to be dedicated to the development of interventions to improve health outcomes and address disparities among PLWH impacted by the COVID-19 pandemic.

Long-term immunologic effects of SARS-CoV-2 infection: leveraging translational research methodology to address emerging questions

The current era of COVID-19 is characterized by emerging variants of concern, waning vaccine- and natural infection-induced immunity, debate over the timing and necessity of vaccine boosting, and the emergence of post-acute sequelae of SARS-CoV-2 infection. As a result, there is an ongoing need for research to promote understanding of the immunology of both natural infection and prevention, especially as SARS-CoV-2 immunology is a rapidly changing field, with new questions arising as the pandemic continues to grow in complexity. The next phase of COVID-19 immunology research will need focus on clearer characterization of the immune processes defining acute illness, development of a better understanding of the immunologic processes driving protracted symptoms and prolonged recovery (ie, post-acute sequelae of SARS-CoV-2 infection), and a growing focus on the impact of therapeutic and prophylactic interventions on the long-term consequences of SARS-CoV-2 infection. In this review, we address what is known about the long-term immune consequences of SARS-CoV-2 infection and propose how experience studying the translational immunology of other infections might inform the approach to some of the key questions that remain.

Seroprevalence of measles vaccine antibody response in vertically HIV-infected children, in Morocco

BACKGROUND

The widespread use of an effective and safe vaccine to measles has substantially decreased morbidity and mortality from this epidemic. Nevertheless, HIV-infected children vaccinated against measles may develop an impaired vaccine response and remain susceptible to this disease. In Morocco, infants are routinely vaccinated against measles, regardless of their HIV serostatus. An evaluation of the immunization of these children may be of paramount importance to implement timely measures aimed at preventing measles transmission.

METHODS

In this study, we have enrolled 114 children vaccinated against measles, 50 children prenatally infected with HIV and 64 HIV-uninfected children. For all children, blood samples were taken to measure anti-measles IgG by EIA and CD4 count by flow cytometry. Additionally, HIV viral load was determined by automated real time PCR, for HIV-infected children.

RESULTS

The seroprotective rate of IgG anti-measles antibodies was significantly lower among HIV-infected children (26%) compared with HIV-uninfected children (73%) (p < 0.001). Within HIV-infected children group, the comparison of variables between children without seroprotective seroconversion to measles and those with seroprotective immunity, displayed that sex and age were not statistically different, p > 0.999 and p = 0.730, respectively. However, CD4 count was lower among children with negative serostatus to measles (23% versus 32%, p < 0.001). Furthermore, viral load was higher, with 2.91 log10 ± 2.24 versus 1.7 log10 ± 1.5 (p = 0.042). Finally, 62% of children with a negative vaccine response to measles were under HAART therapy, versus 92% (p = 0.008).

CONCLUSION

The majority of HIV-infected children vaccinated against measles develop a suboptimal seroprotective titer, and therefore remain at risk for this highly infectious disease. These data in combination with international recommendations, including recent WHO guidance on vaccination of HIV-infected children, suggest there is a need for national measures to prevent these children from measles.

Safety and Immunogenicity of Measles Vaccination in HIV-Infected and HIV-Exposed Uninfected Children: A Systematic Review and Meta-Analysis

BACKGROUND

HIV-infected and HIV-exposed uninfected (HEU) children have an increased risk of measles that may be due to altered immune responses or suboptimal timing of measles vaccination. We aimed to evaluate the safety and immunogenicity of measles vaccination in HIV-infected and HEU children.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Embase, Cochrane Library, CINAHL, Global Health Library and IndMED on May 9, 2018. Studies were included if they reported on safety or seroresponse (either seroprotection/seropositivity/seroconversion) after measles vaccination in HIV-infected or HEU children. We calculated pooled estimates to compare immunogenicity outcomes between HIV-infected, HEU and HIV-unexposed children, using risk ratios [RRs] (with 95%CIs). PROSPERO registration number: CRD42017057411.

FINDINGS

Seventy-one studies met the inclusion criteria (15,363 children). Twenty-eight studies reported on safety; vaccine-associated adverse events and deaths were uncommon. Sixty-two studies reported on immunogenicity, 27 were included in the meta-analysis. HIV-infected children had lower seroresponse rates after primary vaccination compared with HIV-unexposed (RR 0.74; 95%CI: 0.61-0.90, I 2  = 85.9%) and HEU children (0.78; 0.69-0.88, I 2  = 77.1%), which was mitigated by antiretroviral therapy and time interval between vaccination and serology. HEU and HIV-unexposed children had similar seroresponses. Vaccination at 6-months resulted in similar proportions of HIV-infected children having seroresponse compared with HIV-unexposed (0.96; 0.77-1.19) and HEU children (1.00; 0.73-1.37, I 2  = 63.7%).

INTERPRETATION

Primary measles vaccination at 6-months of age may provide protection against measles during early infancy in settings with high prevalence of maternal HIV-infection, however, further studies are needed to evaluate this strategy in HEU children and HIV-infected children receiving antiretroviral therapy.

FUNDING

South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation in Vaccine Preventable Diseases; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit.

Lymphoid tissue fibrosis is associated with impaired vaccine responses

Vaccine responses vary by geographic location. We have previously described how HIV-associated inflammation leads to fibrosis of secondary lymph nodes (LNs) and T cell depletion. We hypothesized that other infections may cause LN inflammation and fibrosis, in a process similar to that seen in HIV infection, which may lead to T cell depletion and affect vaccine responses. We studied LNs of individuals from Kampala, Uganda, before and after yellow fever vaccination (YFV) and found fibrosis in LNs that was similar to that seen in HIV infection. We found blunted antibody responses to YFV that correlated to the amount of LN fibrosis and loss of T cells, including T follicular helper cells. These data suggest that LN fibrosis is not limited to HIV infection and may be associated with impaired immunologic responses to vaccines. This may have an impact on vaccine development, especially for infectious diseases prevalent in the developing world.

Sustained Responses to Measles Revaccination at 24 Months in HIV-infected Children on Antiretroviral Therapy in Kenya

BACKGROUND

There are limited data on whether HIV-infected children in resource-limited countries who are receiving antiretroviral therapy (ART) are able to produce sustained, protective levels of measles antibody after multiple measles vaccinations.

METHODS

We administered an additional measles vaccine to HIV-infected children 15 months to 12 years of age receiving ART in Nairobi, Kenya. Measles antibody concentrations were determined by enzyme-linked immunosorbent assay at enrollment, 1 month, 12 months and 24 months post revaccination.

RESULTS

At enrollment, 125 (54%) of 232 study participants had protective concentrations of measles antibody. Measles seropositivity increased to 98% of all children at 1 month post revaccination but decreased to 71% at 12 months and 60% at 24 months post revaccination. Measles seroconversion and sustained measles seropositivity among those who were measles seronegative at enrollment was 25% at 24 months post revaccination. In this group, 39% of children with <50 copies/mL plasma HIV RNA measles seroconverted compared to 4% of children with plasma HIV RNA ≥1000 copies/mL (P = 0.018).

CONCLUSIONS

Measles revaccination can result in a sustained antibody response in a subset of HIV-infected children receiving ART, especially among those with HIV suppression.