Corona Immunitas Ticino: functional immunity through vaccines and previous infections

New results are out for the Corona Immunitas Ticino project, the epidemiological study launched in 2020 to assess the spread of coronavirus and the development of immunity in the Ticino population. The study, conducted by the Institute of Public Health of Università della Svizzera italiana and the Department of Business Administration, Health and Social Affairs of SUPSI, in collaboration with the EOC and numerous partners in the area, is part of the broader Corona Immunitas research programme, sponsored by the Swiss School of Public Health (SSPH+).

The Corona Immunitas Ticino and Zurich research groups have published, in the journal Eurosurveillance, findings on immunity in Ticino and Zurich after waves related to Delta and Omicron variants and vaccination campaigns. 

The study focused in particular on so-called "functional immunity," which occurs when, thanks to the vaccine or previous infection, the immune system intervenes more promptly, preventing disease exacerbation but not an infection. The research shows that as of March 2022, about 97% of the population had antibodies to the coronavirus spike protein, with no significant differences in people's age or region of origin.

We heard from Emiliano Albanese, director of the Institute of Public Health and professor at the Faculty of Biomedical Sciences, and Rebecca Amati, a researcher at the Institute of Public Health and project manager of Corona Immunitas Ticino.

What are the main findings of this study?

In Ticino and Zurich, by March 2022, almost all of the study population had developed antibodies to the COVID-19 virus. This was due to the combined effect of the vaccination campaign and the rapid spread of the Omicron variant during the winter. A second interesting result concerns the fact that the developed antibodies showed high neutralising capacity against the virus and the Delta and Omicron variants.

What do such high rates of immunity among the population mean? Is it a reassurance in regards to possible fall and winter waves?

The results suggest that most of the population tested in March 2022 developed antibodies with high neutralising capacity against the virus and the Delta and Omicron variants. This is reassuring for people and the health care system (hospitals, intensive care) because neutralising antibodies help protect against severe forms of COVID-19.

The US government has declared that the vaccine for COVID-19 will become an annual affair like the flu vaccine. Does knowing the immunity among the population help in the management of future booster campaigns?

Knowing immunity among the population has been and continues to be critical to informing the relevant authorities (Federal Office of Public Health and the Federal Immunization Commission). Monitoring the trajectories of antibody response over time will allow decisions regarding upcoming vaccine booster campaigns, taking advantage of the available data to define the timing and categories of people affected.