A team led by the lab of Hao Lin, including HMNL and GeneOne Life Science, published major results on the increase efficacy of COVID-19 vaccines by suction treatment in Science Advances. In this work, it was shown that DNA vaccines could be delivered with 100x greater immune response to rats by applying mild suction (similar to a black head remover) to the injection site. Histology performed by HMNL graduate student Sarah Park confirmed that no cellular damage was caused by the treatment. You can read the paper here. The paper was covered by several news outlets, such as here, here, and here.