Interaction of millimetre waves used in 5G network with cells and tissues of head-and-neck region: A literature review

Fifth-generation mobile technology is supposed to revolutionise the world. It has many features which can benefit humankind, but at the same time, it will expose us to much radiation. Therefore, we need to understand the importance and ill effects of 5 G technology. An online literature search was conducted through PubMed and Scopus databases from April 2021 to May 2021, using the Boolean operators OR, AND and NOT and the keywords '5G Network', 'Human tissues', and 'Animal tissues'. The literature is very scarce in studies on the effects of millimetre waves on various tissues. A total of 1269 studies were identified, and 24 were selected for qualitative evidence synthesis. Randomised control trials, laboratory studies, in-vitro studies, in-vivo studies and ex-vivo studies were included. Data from the studies were collected using the data extraction form, and all the relevant information was summarized. Five of 24 studies were done on animals, four on humans, five on models, and ten on various cells. Ten of 24 studies demonstrated the harmful effects of millimetre waves. Results are ambivalent, and no association is found between particular frequency and impact on tissue, animals or humans. Pathophysiological effects observed in most studies were mild, reversible, and limited to the cellular level. Available evidence reported temperature rise after millimetre wave exposure, which was within safety limits. Any biological impact on a cellular level noticed due to radiation's thermal effects were insignificant and did not affect the organ level. However, only a few studies have mentioned non-thermal impact, but those effects should not be overlooked. Clinical trials on a large population and for a longer duration are required to establish the safety of millimetre waves before deploying a 5G network worldwide.