Science indicates less severe omicron disease

Omicron symptoms, Headache, Fatigue, Runny nose, Sore throat, Sneezing    • COVID cases set to break 200,000 in N...   https://covid.joinzoe.com Fever, cough, anosmia less common Headache, 65% Fatigue, 65% Runny nose, 65% Sore throat, 57% Sneezing, 55% The Australia experiment https://www.reuters.com/business/heal... Record infections Plans to reopen economy Prime Minister Scott Morrison We have to stop thinking about case numbers and think about serious illness, living with the virus, managing our own health and ensuring that we're monitoring those symptoms and we keep our economy going https://www.theguardian.com/australia... Queensland, chief health officer, Dr John Gerrard Omicron, peak at very large numbers in late January or early February We are expecting in the next few weeks very substantial numbers of people are going to be infected I think we just have to assume that all of us are going to be exposed in the next few weeks we can expect very large numbers of cases and in the majority of cases, the vast majority of cases, the symptoms will be mild So clearly the vaccine is working Queensland premier, Annastacia Palaszczuk What we’re doing is telling people to go and get vaccinated. We have … given every Queenslander in this state the opportunity to get vaccinated I’m now urging people in those Indigenous communities to ignore those social media posts and immediately go and get your vaccination SARS-CoV-2 Omicron variant replication in human respiratory tract ex vivo https://www.researchsquare.com/articl... Omicron infects and multiplies 70 times faster than the Delta in human bronchus Omicron variant replicated 10 times less in human lung tissue than the original SARS-CoV-2 virus SARS-CoV-2 Omicron-B.1.1.529 Variant leads to less severe disease than Pango B and Delta variants strains in a mouse model of severe COVID-19 https://www.biorxiv.org/content/10.11... Mice infected with Delta compared to mice infected with Omicron Less severe clinical signs (weight loss) Lower virus loads Less extensive inflammation in the lungs T cell epitopes probably conserved Clinical consequences of infection with the Omicron variant may be less severe, but the higher transmissibility could still place huge burden upon healthcare systems The omicron (B.1.1.529) SARS-CoV-2 variant of concern does not readily infect Syrian hamsters https://www.biorxiv.org/content/10.11... All other SARS-CoV-2 VoCs replicate efficiently in Syrian hamsters In hamsters that had been infected with omicron, a 3 log10 lower viral RNA load was detected in the lungs No infectious virus was detectable in the lungs Histopathological examination, lungs from omicron-infected hamsters, no signs pneumonia. The SARS-CoV-2 B.1.1.529 Omicron virus causes attenuated infection and disease in mice and hamsters https://www.researchsquare.com/articl... B.1.1.529 Omicron isolates Immunocompetent and human ACE2 (hACE2) Expressing mice and hamsters Attenuated lung disease Not as ill Lower viral loads SARS-CoV-2 receptor ACE2 and TMPRSS2 are primarily expressed in bronchial transient secretory cells https://www.embopress.org/doi/full/10... The hyper-transmissible SARS-CoV-2 Omicron variant exhibits significant antigenic change, vaccine escape and a switch in cell entry mechanism https://www.gla.ac.uk/researchinstitu... https://www.gla.ac.uk/media/Media_829... Omicron, markedly decreased neutralisation in serology In order Three doses of vaccine Immunity from natural infection (without vaccination) Two doses of vaccine Omicron, compared to Delta and Wuhan D614G Titres of the Omicron variant in lung tissue, were at least an order of magnitude lower at each time point compared to the other two variants This is consistent with attenuated replication of Omicron in lower respiratory tissues as recently reported