Repeated vaccination of inactivated SARS-CoV-2 vaccine dampens neutralizing antibodies against Omicron variants in breakthrough infection

Neutralization of SARS-CoV-2 BQ.1.1 and XBB.1.5 by Breakthrough Infection Sera from Previous and Current Waves in China

“…In addition, for people with Omicron breakthrough infections, a previous booster vaccination did not elicit higher neutralizing activity. Gao et al also reported that in patients with BA.2 breakthrough infection, additional doses of prototype vaccine might recall a robust immune response to target the original strain, but dampen immune responses to newly infected strains 43 . When compared in parallel (Fig.…”

“…In addition, for people with Omicron breakthrough infections, a previous booster vaccination did not elicit higher neutralizing activity. Gao et al also reported that in patients with BA.2 breakthrough infection, additional doses of prototype vaccine might recall a robust immune response to target the original strain, but dampen immune responses to newly infected strains(Gao et al ., 2023). When compared in parallel (Figure 5), sera from the recent BA.5 or BF.7 breakthrough infections exhibited the highest neutralizing activity against all Omicron sub-lineages, indicating that people vaccinated previously and infected in the current wave in China should have a certain degree of protection against re-infection by the emerging Omicron subvariants including BQ and XBB.…”

Impact of National Omicron Outbreak at the end of 2022 on the future outlook of COVID-19 in China

“…Nonetheless, the value of such bivalent vaccines was questioned [ 23 ]. There are basic design questions to be answered: (1) whether the second immunogen, covering one particular variant of Omicron, would be outdated by the time such vaccine is used in large populations as newer Omicron variants would have already emerged and (2) by one injection of the bivalent COVID-19 vaccine, it is questionable whether the body’s immune system will provide a strong immune response toward the first immunogen but not the second immunogen, a phenomenon well known as “original antigenic sin” [ 24 ].…”

Infection of Omicron BA.5.2 in patients provides broad immune responses against SARS-CoV-2

“…Among the existing SARS-CoV-2 vaccines, inactivated vaccine is one of the most widely used and technologically developed vaccines in China. Over 91% of the population in China had received a full primary COVID-19 vaccination schedule and more than 53% of the vaccinated population had received a booster shot [1,2]. However, the population immunity induced by vaccines could be insu cient to prevent SARS-CoV-2 outbreak.…”