tetano
Editor, Senior Moderator
J Clin Virol
. 2026 Jan 10:182:105912.
doi: 10.1016/j.jcv.2026.105912. Online ahead of print. A series of diagnostic contamination events from seasonal influenza vaccines
Andreas Rohringer[SUP] 1 [/SUP], Marit H Ebbesen[SUP] 2 [/SUP], Even Fossum[SUP] 3 [/SUP], Randi M Nygaard[SUP] 4 [/SUP], Birgitte B Madsen[SUP] 5 [/SUP], Margrethe Storm[SUP] 6 [/SUP], Nina Aasand[SUP] 7 [/SUP], Kjersti Rydland[SUP] 8 [/SUP], Karoline Bragstad[SUP] 9 [/SUP], Olav Hungnes[SUP] 10 [/SUP]
Affiliations
Background: Polymerase chain reaction (PCR) is preferred for diagnosing influenza, allowing differentiation between influenza A and B viruses and their subtypes/lineages. However, PCR's high sensitivity can lead to false positives from contamination. During the 2022-2023 influenza season in Norway, a pattern of diagnostic samples testing positive for both influenza A and B or the presumably extinct B/Yamagata lineage suggested external contamination.
Methods: We conducted PCR testing for these samples, environmental samples from vaccination sites, and vaccines, alongside a retrospective review of test data.
Results: This review revealed an increased frequency of unusual detection patterns, particularly during weeks 42-46 of 2022, aligning with the peak of the vaccination campaign. During this period, suspected vaccine-contaminated samples comprised 3.45 % of all influenza-positive samples. Environmental sampling at vaccination sites confirmed the presence of influenza A and B RNA, supporting suspicion of vaccine-derived contamination. Detection in suspect diagnostic specimens of multiple influenza types/subtypes/lineages, including the extinct B/Yamagata lineage, corroborated the seasonal influenza vaccine's contamination source.
Conclusion: These findings highlight the risk of diagnostic sample contamination with RNA from influenza virion-derived vaccines, impacting diagnostic accuracy and public health surveillance.
Keywords: Contamination; Diagnostic test; Inactivated vaccine; Influenza.
. 2026 Jan 10:182:105912.
doi: 10.1016/j.jcv.2026.105912. Online ahead of print. A series of diagnostic contamination events from seasonal influenza vaccines
Andreas Rohringer[SUP] 1 [/SUP], Marit H Ebbesen[SUP] 2 [/SUP], Even Fossum[SUP] 3 [/SUP], Randi M Nygaard[SUP] 4 [/SUP], Birgitte B Madsen[SUP] 5 [/SUP], Margrethe Storm[SUP] 6 [/SUP], Nina Aasand[SUP] 7 [/SUP], Kjersti Rydland[SUP] 8 [/SUP], Karoline Bragstad[SUP] 9 [/SUP], Olav Hungnes[SUP] 10 [/SUP]
Affiliations
- PMID: 41529325
- DOI: 10.1016/j.jcv.2026.105912
Background: Polymerase chain reaction (PCR) is preferred for diagnosing influenza, allowing differentiation between influenza A and B viruses and their subtypes/lineages. However, PCR's high sensitivity can lead to false positives from contamination. During the 2022-2023 influenza season in Norway, a pattern of diagnostic samples testing positive for both influenza A and B or the presumably extinct B/Yamagata lineage suggested external contamination.
Methods: We conducted PCR testing for these samples, environmental samples from vaccination sites, and vaccines, alongside a retrospective review of test data.
Results: This review revealed an increased frequency of unusual detection patterns, particularly during weeks 42-46 of 2022, aligning with the peak of the vaccination campaign. During this period, suspected vaccine-contaminated samples comprised 3.45 % of all influenza-positive samples. Environmental sampling at vaccination sites confirmed the presence of influenza A and B RNA, supporting suspicion of vaccine-derived contamination. Detection in suspect diagnostic specimens of multiple influenza types/subtypes/lineages, including the extinct B/Yamagata lineage, corroborated the seasonal influenza vaccine's contamination source.
Conclusion: These findings highlight the risk of diagnostic sample contamination with RNA from influenza virion-derived vaccines, impacting diagnostic accuracy and public health surveillance.
Keywords: Contamination; Diagnostic test; Inactivated vaccine; Influenza.