Corona study shows herd protection within households

At the national level, “herd protection” against Covid-19 can only be achieved with very high vaccination rates. Austria is still a long way from this. But within households, vaccinated or convalescent people provide such protection, which can be up to 97 percent. That’s what a brand new Swedish study revealed.

Peter Nordström from the University of Umea and his co-authors have now published their scientific study in JAMA Internal Medicine of the US Medical Association (October 11). At the same time, they showed what is possible in a digitized healthcare system with corresponding data.

In the study, they evaluated the Covid-19 data (living together in households, vaccination, survived illness) of 4.9 million citizens according to their identification number given by the state at birth and compared the information.

The study population eventually consisted of nearly 1.8 million people from 814,000 households. Each person who had acquired immunity through illness or vaccination was compared to a person in a comparison group of households in which this had not been the case.

Reduced risk of infection

The first observation: within a mean period of 26 days, 5.7 percent of the participants became infected with SARS-CoV-2.

The infection rates differed greatly from household to household: If only one person in a family was sick with Covid 19 or had received the full vaccination, the risk of infection for those who were not protected was reduced by 45 percent to 61 percent. In the case of two family members with immunological protection, the risk of infection decreased in the other household members by 75 percent to 86 percent.

In families with three vaccinated or convalescent people, the protection rate was between 91 percent and 94 percent. Families with five immunized “naturally” or vaccinated had a protection rate of 97 percent for the rest of the household members.

Vaccination also protects your loved ones

“These results (with regard to the infections; note) were similar to those of the Covid-19 diseases, for which hospital admission was necessary due to the severity of the course of the disease,” wrote the scientists in JAMA Internal Medicine.

Every person who is vaccinated against SARS-CoV-2 also contributes to the protection of their loved ones who have no immunological protection against the coronaviruses. This applies both to a new infection itself and to Covid 19 diseases with a severe course.

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