Researchers have sequenced the partial genomes of two influenza samples and the full genome of another from the 1918 pandemic, Science reports.
It adds that two samples came from lung tissues from German soldiers who died in Berlin in June 1918 that were then preserved in formalin and the third from a woman in Munich who died at an unknown time in 1918. The researchers, led by the Robert Koch Institute's Sébastien Calvignac-Spencer, report in BioRxiv that they compared these sequences from the first and milder wave of the influenza pandemic to ones previously analyzed from later in the influenza pandemic. They uncovered two sites in the nucleoprotein gene that differed between the waves that may have made the influenza virus more resistant to the host viral response.
"It could be a sign that the virus was evolving to better avoid the human immune response in the first months of the pandemic," Calvignac-Spencer tells Science.