BETHESDA, MD – While vaccination is the most important preventive strategy against influenza, post-vaccination antibody responses are often inadequate, especially among HIV-infected persons, according to a new study.

The report, published recently in the journal Vaccine, pointed out that vitamin D deficiency has been suggested to adversely influence immune responses and is highly prevalent among HIV-infected adults.1

To better understand the connection, a study team led by Uniformed Services University of the Health Sciences researchers evaluated the association between 25-hydroxyvitamin D [25(OH)D] levels and post-influenza vaccination responses.

The prospective cohort study sought to evaluate the immunogenicity of monovalent influenza A (H1N1) vaccination among both HIV-infected and HIV-uninfected adults, 18- 50 years old, during the 2009-2010 influenza season. Included were 128 adults, 64 of them HIV-infected with a median CD4 count of 580cells/mm(3), and 64 were HIV-uninfected.

For the research, antibody titers were evaluated at baseline, day 28, and six months post-vaccination using hemagluttination inhibition assays, while serum 25(OH)D levels were measured at day 28.

Results indicated that seroconversion at day 28 post-vaccination was achieved in fewer HIV-infected participants compared with HIV-uninfected participants –56% vs. 74%. In addition, vitamin D deficiency was found to be more prevalent among HIV-infected persons vs. HIV-uninfected persons — 25% vs. 17%.

Yet, no associations were identified between lower 25(OH)D levels and poorer antibody responses at day 28 or six months for any of the study outcomes among either HIV-infected or HIV-uninfected adults.

“Vitamin D deficiency was common among both HIV-infected and HIV-uninfected adults, but lower levels did not predict antibody responses after H1N1 (2009) influenza vaccination,” study authors conclude. “Low 25(OH)D levels do not explain poorer post-vaccination responses among HIV-infected persons.”

  1. Crum-Cianflone NF, Won S, Lee R, Lalani T, Ganesan A, Burgess T, Agan BK. Vitamin D levels and influenza vaccine immunogenicity among HIV-infected and HIV-uninfected adults. Vaccine. 2016 Sep 22;34(41):5040-6. doi: 10.1016/j.vaccine.2016.06.019. PubMed PMID: 27577557.