Machado and co-workers from Brazil recently published robust biological data on the possible role of hypertonic saline solution (HS) as a prophylactic and alternative therapy option for COVID-19 in a preprint report. On the basis of their in vitro experiments in epithelial cells of monkeys (Vero cells), they were able to prove that 1.5% NaCl solution can completely block the SARS-CoV-2 replication. They assume that it is an intracellular mechanism of action and that the inhibiting effect of HS on the life cycle of the virus is due to the depolarization of the plasma membrane8.
These results can be put in connection with earlier in vitro data, which certify hypertonic saline solution in addition to the secretolytic, also anti-inflammatory and anti-infectious effects9.
In RSV infections of the upper respiratory tract it has already been clinically shown that nasal rinsing and gargling with HS (2-3%) shortens the duration of the infection and can reduce OTC medication, the transmission between people in a household and virus shedding10. Currently, two clinical studies with HS as a nasal rinse are also being carried out for COVID-1911, 12 in order to prove the effectiveness of HS against SARS-CoV2 in vivo as well.
Due to Machado HS could lead to simple, safe and low-cost interventions at various stages of COVID-19 treatment, improving the prognosis of infected patients, thereby mitigating the social and economic costs of the pandemic.