In patients with severe lung disease caused by viral infections, physicians sometimes turn to ECMO—a life support machine that takes over the functions of the lungs, heart, or both when other support options appear to be failing. But initial reports of ECMO use in patients with COVID-19 described very high mortality, and some physicians recommended against its use.

New data from Columbia University and other ECMO centers throughout the world now show that more than 60% of severe COVID-19 patients who received ECMO have survived.

“The results of this large-scale international registry study, while hardly definitive evidence, provide a real-world understanding of the potential for ECMO to save lives in a highly select population of COVID-19 patients,” says senior author Daniel Brodie, MD, professor of medicine at Columbia University Vagelos College of Physicians and Surgeons and director of the Adult ECMO Program at NewYork-Presbyterian/Columbia University Irving Medical Center.

To test whether LAIV is effective via intradermal route, 10⁶ plaque forming units (PFU) of DelNS1-LAIV was i.d. injected to multiple groups of mice. One of the groups was boosted with second injection at 14 days after the prime vaccination. Unvaccinated control mice were injected with the same volume of PBS. The mice were intranasally challenged with 10x LD₅₀ of H1N1/415742Md at 28 days after primary vaccination. Both single dose and two doses of i.d. vaccination induced good protection with no weight loss and 100% survival after virus challenge (Fig. 1a). Comparing i.d. vaccinated mice with i.n. vaccinated mice, there was no difference in body weight loss or survival rate (Fig. 1a), which suggested LAIV i.d. vaccination offered the same protective efficacy as i.n. vaccination. Remarkably, a single dose of i.d. vaccination fully protected mice against virus challenge with 100% survival and no weight loss (Fig. 1b).

To test the broadness of i.d. vaccination-induced immunity, H7N9 (A/Anhui/1/2013m) or H5N1 (A/VNM/1194/2004) challenges were performed at 28 days after a single dose of i.d. vaccination. H7N9 challenge caused sharp weight loss and 60% death in PBS control mice, while the vaccinated mice were 3 days quicker in body weight recovery and had 100% survival (Fig. 1c). However, i.d. DelNS1-LAIV only rescued the survival rate to 20% among the H5N1-challenged mice, versus 100% mortality in the PBS group (Fig. 1d).

We then studied the longevity of i.d. DelNS1-LAIV-induced immunity by challenging the vaccinated mice at 3 or 6 months after vaccination. Firstly, homologues virus H1N1/415742Md challenge did not cause body weight loss, nor lethality 3 or 6 months after vaccination (Fig. 1e), suggesting the protective immunity lasted at least for 6 months; Secondly, all vaccinated mice survived against an antigenically different H1N1 strain (PR8) challenge and regaining body weight starting day 7 post challenge (7dpi) (Fig. 1f). All vaccinated mice survived after H7N9 challenge though with a similar degree of weight loss comparing to the PBS control mice (Fig. 1g). The immunized mice challenged by H5N1 at 3 or 6 months had 30% and 20% survival, respectively, with a similar degree of weight loss comparing to the PBS controls (Fig. 1h).