Good timing is often a key to success. This apparently also applies to surviving the omicron wave: Research results from Japan indicate that a Covid-19 vaccination, which is followed months later by an infection with Sars-CoV-2, provides better protection against the omicron variant offers as a vaccination breakthrough that occurs comparatively soon after immunization. That could mean that countries with large numbers of infections with other coronaviruses occurring in late 2021 might be better equipped for the Omicron wave in 2022.
In many places, the population has been immunized against Covid-19 through a combination of vaccination and infection. This does not apply to Japan: Here the population is mainly protected by vaccinations with the mRNA vaccines. Takeshi Arashiro of the National Institute for Infectious Diseases in Tokyo and his colleagues wanted to find out whether people are particularly susceptible to omicrons because of this predominantly one-source immunity. So far there have been only a few vaccination breakthroughs in the country, but “we fear that a completely different picture could emerge as soon as the omicron variant spreads in Japan,” explains Arashiro.
The team collected antibodies from people in Japan who received two doses of the Biontech / Pfizer vaccine and later became infected with either the alpha or delta variant. The researchers then tested the ability of these antibodies to protect cells in culture from infection with the coronavirus. They found that the length of time between vaccination and breakthrough correlated strongly with how well the person’s antibodies protected the cells from infection – especially with Omikron.