Researchers from the UK and Netherlands have identified a new highly virulent strain of HIV-1, named the VB (virulent subtype B) variant in The Netherlands. So far, 109 people carrying this new strain have been detected, according to a study reported in the journal Science.

 The viral load of the new variant was found to be about 3.5 to 5.5 folds higher than the current strain implying greater transmissibility. The rate of decline of CD4 cells is doubled in persons infected with the new variant, who already have low CD4 cell counts at the time of diagnosis. Because of the rapid damage to the immune system, the infection may quickly progress to advanced HIV (CD4 cell counts below 350 cells/mm³) in less than a year (9 months) compared to 2-3 years in the persons not carrying this variant. Progression is faster in older age group. However, the CD4 cell recovery and survival rate with this variant were found to be similar to those infected with other HIV strains provided the infection is diagnosed early followed by prompt initiation of treatment.

Analysis of genetic sequences of samples revealed that this new variant has probably been waiting in the shadows in The Netherlands since the 1990s and probably emerged due to de novo mutation and not recombination. Its incidence continued to increase till 2010 and then showed a declining trend, possibly due to availability of advanced treatment, observe the authors.

The authors say, “Our discovery of a highly virulent and transmissible viral variant therefore emphasizes the importance of access to frequent testing for at-risk individuals and of adherence to recommendations for immediate treatment initiation for every person living with HIV.”

Reference

1. Wymant C, et al. A highly virulent variant of HIV-1 circulating in the Netherlands. Science. 2022 Feb 4;375(6580):540-545. doi: 10.1126/science.abk1688.