The breakthrough infection of Omicron can enhance the protection effect of vaccines

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The breakthrough infection of Omicron can enhance the protection effect of vaccines.

The new coronavirus usually infects humans through the respiratory tract and causes damage to the respiratory system and various organs of the human body.

Since the first outbreak at the end of 2019, the novel coronavirus is still raging around the world, causing great negative impact on the world economy and society.

With the large-scale epidemic of the new coronavirus, new virus mutants continue to emerge, such as Alpha, Beta, Gamma, Delta, Omicron, etc., some of which have stronger infection ability or stronger immune escape ability. At present, the world’s most concerned is the Omicron mutant.

On May 18, 2022, researchers from the Gladstone Institutes of the University of California in the United States published a research paper entitled: Limited cross-variant immunity from SARS-CoV-2 Omicron without vaccination in the top international academic journal Nature .

The study showed that Omicron’s breakthrough infection boosted vaccine-induced immunity in vaccinated populations , suggesting that Omicron may be accelerating the end of the pandemic.

In the unvaccinated population, infection with Omicron induces a humoral immune response against the Omicron variant, but does not confer broad protection against other variants.

The breakthrough infection of Omicron can enhance the protection effect of vaccines.

In this study, the researchers analyzed the infection of the original strain, Delta, and Omicron in transgenic mice expressing human ACE2, and detected symptoms in the mice by intranasal infection.

The study found that Omicron-infected mice had milder symptoms, and unlike the original strain and Delta, Omicron replicated at lower levels in the lungs and brains of infected animals, resulting in mild disease, reduced expression of pro-inflammatory cytokines, and increased intrapulmonary Decreased T cell activation.

The breakthrough infection of Omicron can enhance the protection effect of vaccines. Symptoms of Omicron infection are mild

To determine the humoral immune responses induced by infection with the three strains, the researchers collected sera from mice 7 days post-infection and tested the neutralization efficiency against the virus.

As expected, sera from uninfected mice showed no neutralization throughout the process. Sera from mice infected with the original strain effectively neutralized the original strain and to a lesser extent Beta and Delta strains, but not Omicron.

In contrast, serum from Delta-infected mice effectively neutralized Delta, the original strain, Alpha, and to a lesser extent Omicron and Beta.

However, sera from Omicron-infected mice only neutralized Omicron and not the other variants.

Furthermore, these results have been confirmed in unvaccinated patients. In 10 unvaccinated Omicron patients, sera neutralized only Omicron and not other variants.

Among 11 unvaccinated Delta patients, serum neutralized Delta the most efficiently, followed by the original strain, and to a lesser extent Alpha, Beta, and Omicron.

Notably, in vaccinated people, breakthrough infections with Omicron and Delta had high neutralizing titers for all strains, even exceeding those induced by the third dose of Pfizer’s vaccine.

The breakthrough infection of Omicron can enhance the protection effect of vaccines. Omicron, Delta breakthrough infection boosts vaccine immunity

The results showed that breakthrough infections with Omicron, Delta, boosted vaccine immunity , triggering a new “mixed immunity” that was effective against multiple mutant strains.

In conclusion, Omicron infection effectively enhanced vaccine-elicited immunity in vaccinated individuals, and Delta infection also elicited broad cross-variant protection in vaccinated individuals, and this study supports the inclusion of Omicron and Omicron-based vaccines in future vaccines.

The vaccine developed by Delta provides broad protection against new mutant strains.

Reference:
https://www.nature.com/articles/s41586-022-04865-0

The breakthrough infection of Omicron can enhance the protection effect of vaccines.

(source:internet, reference only)

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