There were 15 million reported COVID cases in the second week of 2022, up from 7 million in the first week of 2022 which saw over 1% of the population catching Covid-19 each week in 26 countries. These numbers are of course underestimates of the real case numbers. However, numbers of new deaths reported globally remained stable. Omicron is now in more than 160 countries, rapidly outperforming and replacing Delta; Omicron is now the predominant variant in at least 60 countries.
WHO has highlighted the need for new vaccines, noting that repeated boosters are not a sustainable strategy (several countries are moving ahead with 4th shots) and that the immediate priority is still primary vaccination for the world. See this interim statement on Omicron from WHO: https://www.who.int/news/item/11-01-2022-interim-statement-on-covid-19-vaccines-in-the-context-of-the-circulation-of-the-omicron-sars-cov-2-variant-from-the-who-technical-advisory-group-on-covid-19-vaccine-composition
In at least one US airline, more than 10% of staff tested positive over the past month. Many member airlines continue to struggle with staff absence due to being cases or contacts, presenting another of the many challenges to the industry.
In UK, it appears that the cases may have peaked at 24 days after the emergence of Omicron; if the early decline in cases continues, this would mirror the timing of peak cases that was seen in South Africa (source: Airfinity).
An important study on dynamics of infectivity related to changes in the aerosol microenvironment from Bristol is here - Oswin et al: https://www.medrxiv.org/content/10.1101/2022.01.08.22268944v1.full.pdf
This notes that the amount of viable airborne virus dissipates quickly (most of it within 5 minutes) – with more rapid clearance in a low humidity environment. There are implications for the on-board environment.
There are very few studies so far on vaccine effectiveness against hospitalisation with Omicron, this one from Andrews et al in UK is relatively encouraging: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2115481. Another similar one, previously sent out, was Collie et al showing 70% vs 93% for Delta - https://www.nejm.org/doi/full/10.1056/NEJMc2119270
Another study on waning is here, confirming previous findings - Rössler et al https://www.nejm.org/doi/10.1056/NEJMc2119236
And in Nature a well-referenced look at the limited efficacy of the inactivated virus vaccines against infection with Omicron variant – important because so much of the world has received these vaccines. https://www.nature.com/articles/d41586-022-00079-6
See also Ai et al: https://www.tandfonline.com/doi/pdf/10.1080/22221751.2021.2022440?src=getftr
And Yu et al: https://www.medrxiv.org/content/10.1101/2021.12.17.21267961v1.full.pdf
Clinical outcomes of Omicron – Lewnard et al looked at rates of ICU admission and mortality among cases with Omicron after an outpatient positive test: https://www.medrxiv.org/content/10.1101/2022.01.11.22269045v1
As compared to the rates for Delta, ICU admission rate for Omicron was 26% and mortality just 9%. No Omicron cases received mechanical ventilation, compared to 11 cases with Delta. Median duration of hospital stay was 3.4 days shorter for hospitalized cases with Omicron as compared to Delta variant infections, a 70% reduction in length of stay.
A Yale analysis by Wells et al, of effectiveness of travel-related quarantine, is interesting: https://www.thelancet.com/journals/lanepe/article/PIIS2666-7762(21)00290-8/fulltext. For nearly half of origin-destination country pairs analysed, travel can be permitted in the absence of quarantine and testing. For the majority of pairs requiring controls, a short quarantine with testing could be as effective as a complete travel ban. The estimated travel quarantine durations are substantially shorter than those specified for traced contacts.
Some other more specific papers:
Increasing confidence in neutralising antibodies as a correlate of protection in JAMA: https://jamanetwork.com/journals/jama/fullarticle/2787928
A summary in Nature on the T-cell response of Omicron: https://www.nature.com/articles/d41586-022-00063-0. As noted previously, antibodies do not tell the whole story.
Also – Interval between infection and vaccination determines strength of hybrid immunity in protecting against Omicron.
Miyamoto et al: https://www.medrxiv.org/content/10.1101/2021.12.28.21268481v1.full.pdf
A useful summary in Nature “COVID vaccines safely protect pregnant people: the data are in“ https://www.nature.com/articles/d41586-022-00031-8
Viral load may be no greater in Omicron than Delta suggesting other factors (immune escape, asymptomatic infection) underlying its transmissibility Puhach et al: https://www.medrxiv.org/content/10.1101/2022.01.10.22269010v1.full.pdf
From 15 January, Canada requires that foreign flight crews, including on cargo operations, may only enter if fully vaccinated (at least 14 days since second dose). Details here as announced previously.
Finally on other matters: Canadian regulations, called the Accessible Transportation Planning and Reporting Regulations (ATPRR) were published 22 December 2021. The ATPRR require airlines with more than 100 employees serving the Canadian market to issue an initial accessibility plan by 1 June 2023 and then updates every three years. A dedicated webpage which contains all information related to the ATPRR, including plain language summaries, FAQs, and guidance material.
Best wishes,
David Powell
IATA Medical Advisor