Covid-19 virus can last in lungs for up to two years: Study

SARSCoV2 the virus causing Covid19 can last in the lungs of certain individuals for up to 18 months after infection finds a studyThe study published in the journal Nature Immunology showed that Covid19 virusrsquo persistence appears to be linked to a failure of innate immunity the first line of defence against pathogensOne to two weeks after contracting Covid the SARSCoV2 virus generally becomes undetectable in the upper respiratory tractBut some viruses persist in the body in a discreet and undetectable manner after causing an infection They remain in what are known as lsquoviral reservoirsrsquo even though it remains undetectable in the upper respiratory tract or bloodThis is the case for HIV which remains latent in certain immune cells and can reactivate at any time It could also be the case for the SARSCoV2 virus which causes Covid19 said the team from the Institut Pasteur who first hypothesised the theory in 2021 and now confirmed it in a preclinical model of a nonhuman primateWe observed that inflammation persisted for long periods in primates that had been infected by SARSCoV2 We therefore suspected that it could be due to the presence of the virus in the body explains Michaela MullerTrutwin Head of the Institut Pasteurs HIV Inflammation and Persistence UnitTo study the persistence of the SARSCoV2 virus the scientists analysed biological samples from animal models that had been infected by the virusThey found that the amount of persistent virus in the lungs was lower for the Omicron strain than for the original SARSCoV2 strainWe were really surprised to find viruses in certain immune cells alveolar macrophages after such a long period and when regular PCR tests were negative said Nicolas Huot researcher in the Institut Pasteurs HIV Inflammation and Persistence UnitWhats more we cultured these viruses and were able to observe using the tools we developed to study HIV that they were still capable of replicatingTo understand the role of innate immunity in controlling these viral reservoirs the scientists then turned their attention to NK natural killer cellsThe cellular response of innate immunity which is the bodys first line of defence has been little studied in SARSCoV2 infections until now said MullerTrutwinYet it has long been known that NK cells play an important role in controlling viral infectionsThe study shows that in some animals macrophages infected with SARSCoV2 become resistant to destruction by NK cells While in others NK cells are able to adapt to infection known as adaptive NK cells and destroy resistant cells in this case macrophagesInnate immunity therefore appears to play a role in the control of persistent SARSCoV2 viruses the team saidThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever