Booster vaccination can reduce breakthrough infection risk in HIV patients

Coronavirus disease 2019 (COVID-19) breakthrough infections in fully vaccinated individuals are a subject of major concern. A booster vaccine dose is recommended for individuals at high risk of breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, including immunocompromised individuals such as human immunodeficiency viruses (HIV) patients.

The study

In a recent study posted on the medRxiv* pre-print server, researchers compared the risk of SARS-CoV-2 breakthrough infection among fully vaccinated people with HIV (PWH) and people without HIV (PWoH).

The study retrieved data from the corona-infectious-virus epidemiology team (CIVET) – II cohort consisting of four longitudinal cohorts from academic health centers and integrated health systems. From each cohort, individuals aged 18 years and above and those who were fully vaccinated (completed 14 days after the second dose of BNT162b2 (Pfizer) or mRNA-1273 (Moderna) vaccines or 14 days after a single dose of the Jansen Ad26.COV2.S 110 [Johnson & Johnson (J&J)] viral vector vaccine) between 11 December 2020 to 30 June 2021 were identified.

Findings

A total of 109,599 fully vaccinated people were included in the study among which 31,840 were PWH and 77,759 were PWoH. The researchers matched PWH and PWoH on parameters such as date fully vaccinated, age group, race/ethnicity, and gender.

The incidence rate per 1,000 person-years (PY) of breakthrough infections was estimated with respect to HIV status, and the results showed the overall incidence rate of breakthrough infections to be 35 per 1,000 PY. The incidence rate of breakthrough infections in PWH was higher (44 per 1,000 PY) than that in PWoH (31 per 1,000 PY).

Stratification by vaccine-type indicated that people who received the J&J vaccine showed the highest incidence rate of breakthrough infections (59 per 1,000 PY), followed by Pfizer (40/ 1,000 PY), and Moderna (26 per 1,000 PY), and a higher rate of breakthrough infections was seen in PWH compared to PWoH for all vaccine types. Stratification by calendar time showed a higher rate of breakthrough among PWH, especially in July and August of 2021.

The cumulative incidence of breakthrough infections at 210 days post-full vaccination was estimated by HIV status and indicated an overall cumulative incidence of 2.3%; the cumulative incidence was higher in PWH at 2.8% compared to PWoH at 2.1%. The risk difference between the cumulative incidences of breakthrough infection showed that PWH exhibits a 0.68% higher risk than PWoH.

The association of CD4 count and HIV viral load with the risk of breakthrough infection was determined and the results showed that PWH with lower CD4 counts at full vaccination had a higher cumulative incidence of breakthroughs and PWH with unsuppressed HIV viral load had a higher risk of breakthrough infection in comparison to those with suppressed viral load (88% of PWH were virally suppressed at 622 cells/mm median CD4 count). However, these findings were not statistically significant.

The Cox proportional hazards model was used to estimate adjusted hazard ratios (aHR) of breakthrough infections by HIV status after adjusting age, prior COVID-19 history, vaccine type, calendar time, and cohort.

The results revealed that older aged individuals (55-74 years) exhibit a lower risk of breakthrough infections while younger individuals [18-24 years] had a high risk of breakthrough infections than individuals aged 44-54 years.

Among the study participants, 51%received the Pfizer vaccine, 43% received the Moderna vaccine, and only 6% received the J&J vaccine. The risk of breakthrough at 120 days post-full vaccination varied among different vaccines, with J&J showing the highest risk of breakthrough at 3.3%, followed by Pfizer at 2.6%, and Moderna at 1.7%. The high risk among PWH compared to PWoH was constant in all vaccine types.

Overall, PWH showed a significantly higher risk of breakthrough infections compared to PWoH(aHR=1.41) after adjusting for covariates of interest.

Conclusions

The study findings showed that PWH are at high risk of breakthrough infections compared to PWoH. Factors such as the younger age (18-24 years) in comparison to old age (45-54 years), history of COVID-19 prior to the full vaccination, and vaccination with J&J in comparison to Pfizer and Moderna were associated with increased risk of breakthrough infections in PWH. Also, the association between HIV viral load suppression or CD4 count and breakthrough infection among PWH was not statistically significant. The researchers suggested an additional primary series dose 28 days after the second mRNA dose or a booster dose 2 months after a single J&J dose vaccine to help prevent breakthrough infection in PWH.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Written by

Susha Cheriyedath

Susha has a Bachelor of Science (B.Sc.) degree in Chemistry and Master of Science (M.Sc) degree in Biochemistry from the University of Calicut, India. She always had a keen interest in medical and health science. As part of her masters degree, she specialized in Biochemistry, with an emphasis on Microbiology, Physiology, Biotechnology, and Nutrition. In her spare time, she loves to cook up a storm in the kitchen with her super-messy baking experiments.