In the case of COVID-19 and other SARS viruses, inhalation delivery of ACE2 antibodies by nanoparticles specifically to the lungs is capable not only to deliver them as close as possible to the targeted cellular receptors and preserve their specific activity but also substantially limit the inactivation of ACE2 receptors in other non-targeted organs limiting possible adverse side effects of the treatment. Here, ACE2 is linked to COVID-19.