BA.5 causes more severe disease

UK infections continue upwards https://health-study.joinzoe.com/data Reinfections now common https://www.independent.co.uk/news/he... https://www.science.org/doi/10.1126/s... Generally, infections tend to milder the second or third time round Danny Altmann, professor of immunology, Imperial College London Omicron is poorly immunogenic, which means that catching it offers little extra protection against catching it again Prof Tim Spector There are definitely a lot of people who got Covid at the start of the year who are getting it again, including some with BA.4/5 who had BA.1/2 just four months ago rare to be reinfected with within three months BA.2.12.1, BA.4 and BA.5 escape antibodies elicited by Omicron infection https://www.nature.com/articles/s4158... New sub-variants notably evade the neutralising antibodies elicited by SARS-CoV-2 infection and vaccination Vaccine boosters based on the BA.1 virus (e.g. those developed by Pfizer/BioNTech and Moderna) may not achieve broad-spectrum protection against new Omicron variants Dr. Onyema Ogbuagu, Yale School of Medicine, Connecticut My personal bias is that while there may be some advantage to having an Omicron-specific vaccine, I think it will be of marginal benefit over staying current with the existing vaccines and boosters Despite immune evasion, the expectation can be that vaccines will still protect against serious disease What we’ve learned clinically is that it’s most important to stay up-to-date with vaccines to maintain high levels of COVID-19 antibodies circulating in the blood Kei Sato, University of Tokyo New sub-variants may have evolved to refavour infection of lung cells Risk is potentially greater than that of original BA.2 Dr Stephen Griffin, University of Leeds It looks as though these things are switching back to the more dangerous form of infection, so going lower down in the lung Neutralization Escape by SARS-CoV-2 Omicron Subvariants BA.2.12.1, BA.4, and BA.5 https://www.nejm.org/doi/full/10.1056... Subvariants BA.1 and BA.2, substantial escape from neutralizing antibodies Subvariants BA.4 and BA.5 have identical sequences of spike protein Comparison of neutralizing antibody titer WA1/2020 isolate with BA.1, BA.2, BA.2.12.1, and BA.4 or BA.5 Isolate USA-WA1/2020 from an oropharyngeal swab, returned from China, who and developed clinical disease, January 2020 in Washington, USA In 27 participants, all vaccinated and boosted with Pfizer, And 27 participants who had been infected with the BA.1 or BA.2 median 29 days earlier (range, 2 to 113 days) In the vaccine cohort Participants were excluded, if they had a history of SARS-CoV-2 infection, or a positive result on nucleocapsid serologic analysis, or if they had received another covid vaccine, or an immunosuppressive medication Six months after the initial two BNT162b2 immunizations Neutralizing antibody titer against WA1/2020 = 124 Neutralizing antibody titer against omicron subvarients = 20 Two weeks after administration of the booster dose Neutralizing antibody titer against WA1/2020 = 5,783 Neutralizing antibody titer against BA.1 = 900 BA.2 = 892 BA.2.12.1 = 410 BA.4 or BA.5 = 275 (21 times lower than 5,783) What about natural immunity Among the participants who had been infected with BA.1 or BA.2, 26 had been vaccinated Median neutralizing antibody titer WA1/2020 isolate = 11,050 BA.1 = 1,740 BA.2 = 1,910 BA.2.12.1 = 1,150 BA.4 or BA.5 = 590 (18.7 times less than 11,050) These data show that the BA.2.12.1, BA.4, and BA.5 subvariants substantially escape neutralizing antibodies induced by both vaccination and infection. SARS-CoV-2 omicron variant has continued to evolve with increasing neutralization escape. These findings provide immunologic context for the current surges caused by the BA.2.12.1, BA.4, and BA.5 subvariants, in populations with high frequencies of vaccination and BA.1 or BA.2 infection.