Correction: Nocini et al. Improving Nasal Protection for Preventing SARS-CoV-2 Infection. Biomedicines 2022, 10, 2966

Correction in the Main Text

In the original publication [1], a correction is needed in the first paragraph in Section 3.2.2 as published. Part of the text related to reference 52 of Balmforth et al. (https://pubmed.ncbi.nlm.nih.gov/40374451/) needs to be removed, since the article has been retracted after the publication of the present article. A correction has been made to Section 3.2.2. With this correction, the order of some references has been adjusted accordingly.

• 3.2.2. Human Clinical Studies

Evidence emerged by the study of Figueroa and colleagues, using an IC-containing nasal spray, which was randomly administered with placebo to 394 Hospital workers [52]. All study subjects were asked to self-administer 1 puff (0.10 mL, 0.17 mg of IC or placebo) four times daily in both nostrils. The number of diagnoses of SARS-CoV-2 infection after 21 days of treatment was found to be significantly lower in subjects who used the IC nasal spray (2/196) compared to those who used the placebo (10/198; absolute risk reduction, 4%; 95%CI, 0.6–7.4%). No side-effects analysis was carried out in this investigation.

Paolacci et al. administered a nasal spray containing α-cyclodextrin and hydroxytyrosol to 149 healthy volunteers at high risk of SARS-CoV-2 infection due to their occupation [53]. During 30 days of follow-up, none of these subjects was diagnosed with COVID-19, although no SARS-CoV-2 infection also occurred in 76 control individuals who did not use the nasal spray during the same period. No side-effects analysis was carried out in this work.

Preliminary but interesting evidence has also been provided that an anti-SARS-CoV-2 neutralizing monoclonal antibodies (mAbs)-based nasal spray may provide good protection against SARS-CoV-2 infection. In a small-scale clinical trial, Lin et al. explored the efficacy of a single nasal spray containing the anti-SARS-CoV-2 35B5 mAb, which was tested in 30 healthy volunteers [54]. It was found that the mAB 35B5 concentration in a nasal mucosal specimens remained significant up to 72 h after spray administration (1 mg/mL 35B5 mAb diluted in 50% Dulbecco’s phosphate-buffered saline with 50% glycerol), concomitantly conveying up to 24–48 h efficient in vitro neutralization of several SARS-CoV-2 variants of concern (VOCs), including Omicron.

Recent evidence has been provided that the anticoagulant drug heparin displays pleiotropic antiviral properties, mostly by binding to the spike protein of SARS-CoV-2 and thus inhibiting host cell infection [55]. It is hence not surprising that its administration through the unconventional nasal route has been conceived as a prophylactic treatment against SARS-CoV-2 infection [56]. To this end, Eder et al., carried out a single-center, open-label intervention study aimed at exploring the effect of low molecular weight heparin (LMWH) inhalation for preventing SARS-CoV-2 infection [57]. By means of a nebulizer, 33 subjects received 4500 IU Enoxaparin or placebo in the right or left nostrils, respectively. Nasal epithelial cells were then collected by brushing and exposed to both authentic SARS-CoV-2 isolate and SARS-CoV-2 pseudovirus. In both cases binding to, and infection of, human nasal cells were found to be substantially inhibited by enoxaparin for up to 16 h.

The study protocol of a phase III, double-blind, randomized, single-centre clinical trial for establishing the efficacy of carrageenan-based nasal spray (purified water, 0.5% sodium chloride, 1.2 mg iota-carrageenan and 0.4 mg kappa-carrageenan) for lowering the risk of SARS-CoV-2 infection was presented in September 2022 [58], but results are still unavailable.

The authors state that the scientific conclusions are almost unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.