Pandemic optimism

Natural infection and / or vaccination? and Special report Mississippi https://www.bbc.co.uk/news/health-58270098 Delta in UK Viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK https://www.ndm.ox.ac.uk/covid-19/covid-19-infection-survey/results/new-studies https://www.ndm.ox.ac.uk/files/coronavirus/covid-19-infection-survey/finalfinalcombinedve20210816.pdf Delta infections after two vaccine doses had similar peak levels of virus to those in unvaccinated people Two doses of either vaccine, same level of protection against infection as natural infection Natural infection followed by vaccination, even more protection than vaccination alone After four to five months, effectiveness of these two vaccines similar The time between doses does not affect effectiveness in preventing new infections Now Levels of immunity in the community Implications for vaccination in children Should we use virus or booster shots to top up immunity in adults? Prof Eleanor Riley, immunologist, University of Edinburgh We could be digging ourselves into a hole, for a very long time, where we think we can only keep Covid away by boosting every year Prof Adam Finn, government vaccine adviser Over-vaccinating people when other parts of the world had none a bit insane, it's not just inequitable, it's stupid https://www.nature.com/articles/s41401-020-0485-4 SARS-CoV-2 belongs to the β coronavirus family Seventh known coronavirus to infect humans Four cause colds, 229E, NL63, OC43, and HKU1 SARS-CoV, 2002 MERS-CoV, 2012 SARS-CoV-2, 2019 SARS-CoV-2 Single-stranded RNA-enveloped virus Entire genome, 29,881 bases Encoding 9,860 amino acids 28 proteins essential for infection Breadth of immunity How much of the virus the immune system learns to attack Natural infection, more polyclonal Moderna or Pfizer or Oxford-AstraZeneca, just spike protein Keeps people out of hospital 28 proteins recognised give Lymphocytes a ‘target rich environment’ Prof Eleanor Riley, immunologist, University of Edinburgh That means if you had a real humdinger of an infection, you may have better immunity to any new variants that pop up as you have immunity to more than just spike Strength of immunity Power to prevent infection and cause severe disease In the case of breakthrough infection or reinfection Asymptomatic, low levels of antibodies Symptomatic or ill, higher levels of antibodies Duration of immunity Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection https://www.nature.com/articles/s41586-021-03696-9 Natural infection, no vaccination Antibody to the receptor binding domain, active RBD-specific memory B cells, active and relatively stable between 6 and 12 months after infection Vaccination further increases all components of the humoral response Results in serum neutralizing activities against variants of concern Similar to or greater than the neutralizing activity against the original Wuhan Hu-1 strain achieved by vaccination of naive individuals The data suggest that immunity in convalescent individuals will be very long lasting and that convalescent individuals who receive available mRNA vaccines will produce antibodies and memory B cells that should be protective against circulating SARS-CoV-2 variants. Anatomical location of immunity Immunoglobulin A, mucous membranes Immunoglobulin M and G, in the blood Prof Paul Klenerman, University of Oxford The location of an infection makes a difference even if it's the same virus, so we would expect important differences between natural infection and vaccines Current questions Do vaccinated adults need to be boosted, or is exposure to the virus enough? Do children need vaccinating at all, or does a lifetime of ongoing exposures build a good immune defence? Immune top ups occur with respiratory syncytial virus Learn more about your ad choices. Visit megaphone.fm/adchoices