Nasal sprays for treating COVID-19: a scientific note

Abstract

Clinical management of COVID-19 has been a daunting task. Due to the lack of specific treatment, vaccines have been regarded as the first line of defence. Innate responses and cell-mediated systemic immunity, including serum antibodies, have been the primary focus of practically all studies of the immune response to COVID-19. However, owing to the difficulties encountered by the conventional route, alternative routes for prophylaxis and therapy became the need of the hour. The first site invaded by SARS-CoV-2 is the upper respiratory tract. Nasal vaccines are already in different stages of development. Apart from prophylactic purposes, mucosal immunity can be exploited for therapeutic purposes too. The nasal route for drug delivery offers many advantages over the conventional route. Besides offering a needle-free delivery, they can be self-administered. They present less logistical burden as there is no need for refrigeration. The present article focuses on various aspects of nasal spray for eliminating COVID-19.

Keywords: Clinical trials; Devices; Immunity; Nasal route; Nasal spray; Nasal vaccine; SARS-CoV-2.

Fig. 1

Antibody-induced disease enhancement in macrophage tropic viruses: non-neutralizing or sub-neutralizing antibodies enhance viral infection of monocytes or macrophages through FcγRIIa-driven endocytosis, augmenting the disease (Figure created with biorender.com)

Fig. 2

Antibody-induced disease enhancement in respiratory viruses—immune complexes are formed between non-neutralizing antibodies and viral antigens in the airway tissues, leading to events such as—secretion of pro-inflammatory cytokines, recruitment of immune cells, and activation of the complement cascade in lung tissue. The resulting inflammation can cause airway obstruction and acute respiratory distress syndrome in severe cases. (Figure created with biorender.com)

Fig. 3

Physiological role of nitric oxide. Different actions of nitric oxide may have significance in management of SARS-CoV-2 (Figure created using biorender.com)