HIV could be reducing effectiveness of vaccines

For those of us living with HIV one of the ongoing concerns is picking up new infections. Vaccines can help with this, but for many infections we know that vaccines simply aren't as effective on us as the general population. Why is that?

Research by investigators at the Oregon Health & Science University in Brooklyn is aiming to help answer that very question.

Their work, published in the Journal of Infectious Diseases, studied 50 matched pairs of HIV-negative and HIV-positive women born before 1971 who, as children, had been vaccinated for smallpox.

The team chose Smallpox for their study because it’s been more than 70 years since the last known case in the United States, thus there was no danger of the women having been exposed to the virus in recent years. 

The women were then exposed to Vaccinia, the virus used in the smallpox vaccine, to test their immune system's response. The findings showed that whilst 20% of the HIV-negative women reached the target threshold for CD4 T-cell response to the virus, only 2.4% of the HIV-positive women reached the same target.

The study’s authors say the results show that even though HIV treatment helps restablish the immune system of a person with HIV, this may not hold for some viruses or vaccines that person had in childhood.

They also found that the HIV-positive women showed an increased CD8 T-cell activation, which has been linked to chronic inflammatory state, an acknowledged driver in accelerated or accentuated aging in people with HIV.

If HIV is reducing effectiveness of past vaccines, even after people have commenced HIV treatment, this could increased the risk of common infections among people living with the virus. In particular, common childhood diseases such as measles, mumps, chickenpox and whooping cough may pose a more serious risk than previously thought.

In a press release Michael Augenbraun, MD, a professor of medicine at State University of New York Downstate Health Sciences University and Kings County Hospital Center, said:

“There is no doubt that ART (HIV treatment) provides significant, life-changing benefits for people with HIV by reconstituting their overall immune response.

“What our study suggests is that ART may not be completely effective in restoring the immune protection resulting from viral infections or childhood vaccines received prior to becoming HIV positive.

“This makes these patients potentially susceptible not only to these serious diseases but also other chronic infections and to chronic inflammation that may diminish their overall health and shorten their life span.”

No clinical recommendations were made by the authors of the study, but these findings further underline the need to get people diagnosed early and started on treatment immediately. Hopefully by doing so damage to the immune system's memory can be prevented.