Influenza and HIV are endemic in Nigeria but there is no epidemiological data on the co-infection of influenza A and B among HIV patients.
We investigated seasonal influenza A and B, and co-infection among HIV patients on combined antiretroviral therapy (cART) in Lagos, Nigeria.
In a prospective cross-sectional study, clear sera collected from 174 HIV-positive patients between August and September 2018 were analysed for immunoglobulin M-specific antibodies to seasonal influenza A subtypes H1N1 and H3N2, and influenza B by enzyme immunoassay.
A total of 39.7% (69/174) of HIV patients were seropositive for influenza A or B viruses with 84.1% (58/69) being positive for influenza A, 13.04% (9/69) seropositive for both influenza A and B, and only 2.9% (2/69) positive for influenza B mono-infection. Median age was 44 (mean 45, mode 40, range 18–74) years. The 41–50 years age group had the highest seroprevalence (39.1%; 27/69). Seropositivity was highest among women (65.2%; 45/69). A total of 88.4% (61/69) of HIV patients seropositive for influenza A or B were on fixed dose cART, while 73.9% (51/69) were virologically suppressed. Furthermore, 27.5% (19/69) were immunocompromised, of which 21.1% (4/19) were severely immunosuppressed (cluster of differentiation 4 < 200 cells/mm>3).
Influenza A and B was prevalent among HIV patients on cART, which may predispose them to life-threatening complications. We recommend strong advocacy on the need to reduce the risk of exposure to influenza and for the provision of an influenza vaccine in Nigeria.
In humans, seasonal influenza viruses cause an annual 3–5 million illnesses and 290 000–650 000 deaths worldwide.
On the other hand, HIV is a retrovirus that spreads through the body rapidly, causing damage to the immune system by attacking host cluster of differentiation 4 (CD4) cells with resultant AIDS.
According to the World Health Organization,
Influenza viral infection is a common cause of respiratory illness among HIV-infected persons in whom it can be more severe and prolonged.
In general, the immunogenicity of influenza viral infections in HIV-infected patients is directly proportional to the CD4 cell count and correlates negatively to the viral load.
However, a lack of epidemiological data on seasonal influenza in HIV-positive individuals is a major problem preventing the development of national policies on influenza preventive strategies in sub-Saharan Africa, including Nigeria. In South Africa, 44% of influenza positive patients having acute respiratory infections are HIV-infected.
Serological assays usually complement epidemiological and clinical investigations in the detection and identification of influenza viruses. They measure antibodies developed in response to infection with antigenically novel and seasonal influenza viruses.
This study was therefore designed to investigate seasonal influenza A and B virus infections in HIV patients on cART in Lagos, Nigeria.
Permission was sought from the head of the AIDS prevention initiative in Nigeria (APIN) clinic where the samples were collected after tendering the ethical approval (reference no.: LREC.06/10/1030) obtained from the Health Research and Ethics Committee of the Lagos State University Teaching Hospital (LASUTH).
A prospective cross-sectional study was designed. Outpatients attending the AIDS prevention initiative in Nigeria (APIN)-Lagos University Teaching Hospital clinic who were previously laboratory confirmed to be HIV-positive were recruited for this study from August 2018 to September 2018. APIN-Lagos University Teaching Hospital clinic is a large university-based HIV clinic in Lagos, Nigeria, with about 15 000 patients currently enrolled in Lagos. After explaining the concept of the study, a total of 174 HIV patients, including 165 on cART, who were unvaccinated for influenza and gave both oral and written informed consent, were bled by venepuncture. Demographic and clinical data were appropriately collected with a designed questionnaire. Results of further laboratory analyses including CD4 count, RNA viral load and cART regimen were obtained from the patients’ clinical records.
Approximately 5 mL of whole blood samples were collected into sterile plain bottles. They were stored in sample coolers stacked with ice packs before being conveyed to the laboratory. The samples were centrifuged at 704 × g for 15 min to obtain clear sera that were aliquoted into labelled sterile plain cryovial tubes. The sera were then stored away at −30 °C until ready for serological analysis.
Clear sera were analysed for the detection and quantitative determination of immunoglobulin M antibody specific for influenza virus by enzyme-linked immunoassay (Demeditec Diagnostics GmbH, Kiel, Germany) in the Department of Microbiology (Virology Research) Laboratory, Lagos State University, Ojo. Following manufacturer’s instructions, sufficient amounts of micro titre wells were prepared for the standards, controls and samples as well as for the substrate blank. The samples were diluted with ready-to-use sample diluent provided with the test kit in the ratio 1:100 (2
Raw data were entered into Microsoft Excel, version 2013 (Microsoft Corporation, Redmond, Washington, United States). Descriptive statistics was performed while inferential statistics was analysed with chi-square at
Out of the 174 HIV-positive patients tested, 69/174 (39.7%) were seropositive for influenza A or B viruses, with 58/69 (84.1%) positive for influenza A, 2/69 (2.9%) for influenza B, and 9/69 (13.0%) for both influenza A and B (
Characteristics of HIV patients positive for influenza A and B viruses in 2018 in a university-based HIV clinic in Lagos, Nigeria.
Characteristics | No. of patients ( |
Total influenza positive ( |
Influenza A positive ( |
Influenza B positive ( |
Co-infection of influenza A and B ( |
|||||
---|---|---|---|---|---|---|---|---|---|---|
% | % | % | % | |||||||
Female | 112 | 45 | 65.2 | 38 | 65.5 | 2 | 100 | 5 | 55.6 | 0.61 |
Male | 55 | 17 | 24.6 | 15 | 25.9 | 0 | 0 | 2 | 22.2 | |
Unknown | 7 | 7 | 10.1 | 5 | 8.6 | 0 | 0 | 2 | 22.2 | |
HIV RNA < 400 copies/mL | 144 | 51 | 73.9 | 42 | 72.4 | 2 | 100 | 7 | 77.8 | < 0.001 |
CD4 count < 400 cells/mm3 | 59 | 19 | 27.5 | 15 | 26.0 | 1 | 50 | 3 | 33.3 | < 0.001 |
Combined antiretroviral therapy | 165 | 61 | 88.4 | 52 | 89.7 | 2 | 100 | 7 | 77.8 | < 0.001 |
Note:
CD4, cluster of differentiation 4; RNA, ribonucleic acid; HIV, human immunodeficiency virus.
The most commonly prescribed cART used as a single-pill combination at the APIN clinic included atazanavir, azidothymidine, efavirenz, lamivudine, lopinavir or ritonavir, nevirapine, and tenofovir (
Commonly prescribed combined antiretroviral therapy regimens in HIV patients positive for influenza virus immunoglobulin M antibodies in 2018 in a university-based HIV clinic in Lagos, Nigeria.
cART regimen | No. of patients | Total influenza positive |
Influenza A positive |
Influenza B positive |
Co-infection of influenza A and B |
||||
---|---|---|---|---|---|---|---|---|---|
% | % | % | % | ||||||
FDC (TDF/3TC/EFV) | 74 | 28 | 37.8 | 23 | 82 | 2 | 7.1 | 3 | 10.7 |
FDC (AZT/3TC/NVP) | 64 | 20 | 31.3 | 19 | 95 | 0 | 0.0 | 1 | 5.0 |
FDC (TDF/3TC)-AZT-LPV/r | 4 | 2 | 50.0 | 2 | 100.0 | 0 | 0.0 | 0 | 0.0 |
FDC (TDF/3TC)-LPV/r | 4 | 3 | 75.0 | 2 | 66.7 | 0 | 0.0 | 1 | 33.3 |
FDC (TDF/3TC)-AZT-ATV/r | 3 | 2 | 66.7 | 1 | 50.0 | 0 | 0.0 | 1 | 50.0 |
cART, combined antiretroviral therapy; FDC, fixed dose combination; TDF, tenofovir; 3TC, Lamivudine; EFV, efavirenz; AZT, azidothymidine; NVP, nevirapine; LPV, lopinavir/ritonavir (r); ATV, atazanavir;
HIV, human immunodeficiency virus.
Seroprevalence was highest in patients aged 41–50 years (39.1%; 27/69), with no detections in the age groups 61–70 and 71–80 years (
Age (years) distribution of HIV patients seropositive to influenza in 2018 in a university-based HIV clinic in Lagos, Nigeria.
In this study, we described the recent infection of seasonal influenza A and B, and their co-infection, among HIV patients on cART in Lagos, Nigeria, with a high predominance of influenza A virus. While a high proportion of the patients were virologically suppressed, having HIV RNA under 400 copies/mL, 27.5% of them were immunocompromised while 21.1% were severely immunosuppressed (CD4 < 200 cells/mm3). The hospital population-based study revealed an overall seasonal influenza serological prevalence of 39.7% (69/174) that will serve as a baseline for other studies in Nigeria. We defined the seasonal influenza virus as any type or subtype of influenza virus including influenza A or B that are commonly circulating in our environment at any particular point in time as against a pandemic influenza virus. To our knowledge, this is the first study on clinical and sero-epidemiological prevalence of influenza viruses in HIV patients on cART in Nigeria.
The seroprevalence rate is comparable with the 31% serological response recorded in HIV-positive individuals in Miami, United States.
Our investigation further revealed that 84.1% (58/69) were immunoglobulin M seropositive for influenza A, indicating an epidemiological predominance of the influenza A over the influenza B virus during the study period in Lagos, Nigeria. In a study conducted in Malawi,
Interestingly, 13.04% (9/69) of the HIV patients were seropositive for both influenza A and B viruses. Co-infection of influenza A and B viruses in HIV patients may exacerbate the immunocompromised status by further impairing T-cell responses with resultant fatal consequences in such individuals. This position agrees with previous studies that influenza in HIV-infected persons leads to increased and prolonged hospitalisation, and an elevated risk of in-hospital death.
Our study demonstrated the highest 39.1% seroprevalence of influenza among HIV patients in the age group 41–50 years which disagrees with the United States Centers for Disease Control and Prevention report that persons older than 65 years are more likely to be at risk of the influenza virus.
Based on gender, a higher 65.2% seroprevalence was detected among women compared to 24.6% among men in our study, which is consistent with findings from Malawi
Of the 19/69 (27.5%) immunocompromised patients seropositive for the influenza virus, 4/19 (21.1%) were severely immunosuppressed (CD4 < 200 cells/mm3). However, the role of CD4 and its impact on influenza in HIV-positive patients is poorly understood, partly due to their heterogeneity and lack of epitope-specific systems.
Contrary to studies in South Africa from 2009 to 2011
People with a viral load under 400 copies/mL (73.9%) had the highest seroprevalence of influenza virus. This agrees with a study in the United States between 2010 and 2011
Among the 165 HIV patients on a fixed dose combination of some regularly prescribed cART including tenofovir, emtricitabine, azidothymidine, atazanavir, efavirenz, nevirapine, and lopinavir or ritonavir, 61 (37%) were seropositive for influenza A and B viruses. The direct relationship of cART on patients and their seropositivity to influenza is not well understood. Nonetheless, our study demonstrated that HIV patients on cART were susceptible to recent infection with influenza viruses. In support of this finding, a systematic review done on co-infections and comorbidities of influenza in Africa from 1900 to 2013
One of the limitations of this study is that positive samples for the influenza virus by enzyme linked immunoassay could not be further tested by polymerase chain reaction due to the cost implication. Also, serological evidence from different HIV treatment centres are necessary for representative data in Nigeria. Another limitation is that an HIV-uninfected control group was not included in the study for possible comparison of the prevalence rates of influenza. Finally, it should be noted that the study was conducted over one influenza season and therefore the impact of seasonal changes in influenza strains was not studied. Rather our study has provided sero-epidemiological data on the commonly circulating seasonal influenza virus in HIV patients.
This study demonstrated using serology that HIV patients on cART are susceptible to both influenza A and B viruses. It however revealed low seroprevalence of influenza B mono-infection, and influenza A and B co-infections among HIV patients. Viral co-infections may further impair the already compromised immune system of HIV patients. Strong advocacy on the need to reduce risk of exposure to influenza, and for provision of an influenza vaccine in Nigeria, is recommended to prevent or reduce the complications of viral co-infection.
We sincerely acknowledge all the patients who volunteered to be part of this study. We acknowledge the Lagos State University Teaching Hospital (LASUTH) Directorate of Clinical Services and Training and the Hospital Research Ethics Committee for the approval of the study research proposal. We are grateful to the Management and Staff of APIN-Lagos University Teaching Hospital for the approval for sample collection. Special thanks to all the laboratory technologists who supported the student’s research work. Many thanks to all the senior faculty members who criticised and reviewed the initial manuscript. The abstract for this study was presented at the 52nd Miami Winter Symposium 2019: Evolving Concepts in HIV & Emerging Viral Infections, organised by Elsevier, University of Miami Miller School of Medicine, International Union of Biochemistry and Molecular Biology in Florida, United States (27–30 January 2019).
The authors have declared that no competing interest exists.
A.A.A. was responsible for experimental design and research supervision, data analysis, laboratory investigation and manuscript writing. B.A.A. was responsible for sample collection, laboratory investigation, data analysis and manuscript writing.
This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Data sharing is not applicable to this article as no new data were created or analysed in this study.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any affiliated agency of the authors.