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Canadian researchers study COVID-19 vaccine effectiveness in people who use drugs

SARS-CoV-2 is the virus that causes an illness called COVID-19. Vaccines and booster shots that greatly reduce the risk of COVID-19-related complications, including serious illness, hospitalization and death, are available. Boosters are updated from time to time to enhance protection from variants of SARS-CoV-2, as the virus is constantly mutating.

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Canadian research

A team of Canadian researchers conducted a large study to estimate the effect of COVID-19 vaccination in different populations, including people with a history of injecting drugs.

The researchers analysed health-related information from databases in British Columbia. The information they accessed had been rendered anonymous so that individuals could not be identified. The data were collected between December 2020 and November 2021. Participants had all been tested for SARS-CoV-2 infection and the whole study population was distributed as follows:

  • 2,700 people with HIV
  • 375,043 people without HIV

Researchers divided the study population into four groups:

  • people with HIV who injected drugs
  • people with HIV who did not inject drugs
  • people without HIV who injected drugs
  • people without HIV who did not inject drugs

Results

In general, the researchers’ findings suggested that people with HIV who use drugs may have reduced vaccine effectiveness against the risk of developing COVID-19. A similar finding occurred among people without HIV who used drugs.

Citing their previous studies, the researchers stated that a combination of “substance use and/or comorbidities that occur in [people who inject drugs]” may partially weaken the immune system, which would explain the findings in the present study.

There also may have been unmeasured issues that could have adversely affected the health of people who injected drugs, such as living in close quarters or crowded conditions or having difficulty maintaining physical distancing from other people (to reduce the risk of infection from SARS-CoV-2).

The researchers hope to conduct future analyses and refine their findings.

Help for people who inject drugs

The researchers suggested that that people who inject drugs should be prioritized for receiving booster doses of COVID-19 vaccines.

They noted that people who inject drugs face stigma and discrimination and can develop mistrust of the medical system. Therefore, interventions to reach people who inject drugs will require strategies to overcome these barriers.

—Sean R. Hosein

REFERENCE:

Puyat JH, Wilton J, Fowokan A, et al. COVID-19 vaccine effectiveness by HIV status and history of injection drug use: a test-negative analysis. Journal of the International AIDS Society. 2023 Oct;26(10):e26178.