Zambian study finds no link between HIV status and COVID-19 severity, but risk quadruples for people with severe HIV infection

Having HIV is not an independent risk factor for severe COVID-19 and death amongst patients hospitalised with COVID-19, according to a Zambian study published in the Morbidity and Mortality Weekly Report. However, patients with more severe HIV infection are more likely to develop severe COVID-19 or die of COVID-19 compared to those without complications.

“This finding is consistent with results from smaller studies among hospitalised patients in North America, Europe, and South Africa,” state the authors. The results highlight that maintaining access, and support for adherence, to antiretroviral therapy (ART) is important for reducing the impact of COVID-19 on individuals and the healthcare system as well as for improving HIV outcomes.

Research into the effect of HIV on COVID-19 outcomes has so far yielded mixed results. A large South African study found that having HIV doubled the risk of death from COVID-19, and these findings have been supported by two UK studies. However, other research from the UK and US suggests that HIV is not an independent risk factor for more severe COVID-19 and death.

Like many sub-Saharan African countries, the prevalence of HIV in Zambia’s general population is very high (around 12%) and its healthcare system’s capacity to treat severe COVID-19 is limited. Understanding whether HIV increases the risk of severe COVID-19 and death is therefore of urgent importance in this context.

Accordingly, a team of researchers led by Dr Duncan Chanda of the Zambian Ministry of Health undertook a prospective cohort study of COVID-19 patients admitted for care in five specialised COVID-19 treatment centres in four Zambian cities between March and December 2020. Their aim was to establish whether COVID-19 patients living with HIV were at greater risk of severe COVID-19, at admission or during hospitalisation, and death.

Severe COVID-19 was defined as having an oxygen saturation lower than 90%, a respiratory rate above 30 breaths per minute, or a need for oxygen therapy.

A total of 443 patients with a COVID-19 diagnosis, either confirmed by a PCR or rapid antigen test or assumed to be probable due to acute respiratory symptoms, were included in the study. One hundred and twenty-two (28%) were living with HIV and of these, 91 (89% of those with data) were receiving ART at the time of hospitalisation.

Although the mean age of participants was similar regardless of HIV status, HIV-negative participants were more likely to be aged over 60. HIV-positive participants were more likely to be anaemic or severely anaemic, and to report having two or more underlying medical conditions.

After controlling for these differences and other potential confounders, the researchers found that having HIV was not in itself associated with a higher risk of severe COVID-19 or death. In contrast, being aged over 60 and having two or more underlying medical conditions were associated with higher risk of both, while being male was associated with a higher risk of death.

Thirty-seven of the participants living with HIV were classified as having severe HIV infection – defined as having severe anaemia (n=11), a CD4 count below 200 (n=16), active TB (n=16), or a BMI lower than 18.5kg/m² (n=10). Some participants met more than one criterion for severe HIV infection.

These participants were found to be nearly four times more likely to have severe COVID-19 at admission (aOR 3.91; 95% CI 1.69, 9.69) or during hospitalisation (aOR 4.42; 95% CI 1.83, 11.66) and three times more likely to die (aOR 3.27; 95% CI 1.21, 8.79), compared to the other participants living with HIV.

The study authors do advise caution when interpreting their results. They highlight that other, larger cohort studies in South Africa and the UK have found that HIV alone is an independent risk factor for more severe COVID-19 and death, while smaller studies such as this one have not. Their results could also be biased since the study only included hospitalised patients who may differ systematically from the general population. In addition, measures of HIV status and underlying health conditions mostly relied on patient self-report, and data records for measures such as CD4 count were incomplete.  

Nonetheless, the authors state that these findings “underscore the importance of Zambia’s progress toward ending the HIV epidemic and of efforts to maintain HIV services during the COVID-19 pandemic.” Across sub-Saharan Africa, maintaining access and supporting adherence to ART, as well as addressing other underlying medical conditions, is likely to improve both HIV and COVID-19 outcomes and reduce COVID-19 associated death.