Putting your hands in the soil can affect the immune defence system's ability to respond to the vaccine

A study by the Natural Resources Institute Finland (Luke) and the Tampere University examined whether dermal exposure to natural microbes can modulate immune defence and pneumococcal vaccine response.

Streptococcus pneumoniae is a bacterium that causes upper respiratory tract infections such as sinus and otitis media. Every year, 10 million children are born, who are vaccinated but remain unprotected from pneumococcus due to vaccine ineffectiveness. For the elderly, vaccine ineffectiveness is even more dangerous, making it particularly important to develop new ways to improve vaccine response. Microbially oriented biodiversity interventions have demonstrated benefits for immune regulation. However, how microbial biodiversity affects vaccine responses has not been studied before.

In this experiment, healthy adults in the exposure group rubbed their hands in a microbially rich soil before breakfast, lunch and bedtime and then rinsed their hands with water for two weeks. The microbially rich soil used has been thoroughly tested in the past and found to be safe.

Each member of the exposure group had a ‘control pair’ of the same sex and age, and matched housing type and pet ownership. The control pairs did not rub their hands in the soil. In total, there were 50 subjects, i.e. 25 pairs.

After two weeks, the exposure and control groups received a pneumococcal vaccine. The cell-mediated immunity of the exposure and control groups responded differently to the pneumococcal vaccine, although the vaccine response was effective in both groups. Only the skin and gut microbiota of the exposure group changed during the experiment. In addition, only in the exposure group was the gut bacterial community associated with the response to the anti-inflammatory cytokine interleukin 10 in cellular assays.

It is therefore possible that exposure to natural microbes affects the vaccine response, which may also be true for the influenza and coronavirus vaccine response. The finding that environmental biodiversity can alter vaccine response is very important, but further research is needed.