INTERNATIONAL AIRLINE MEDICAL ASSOCIATION

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Hospitalisations are rising in several European countries, following earlier increases in cases with an apparent global fifth wave.  The hospitalisation figures do not distinguish between those admitted for COVID, and those (anecdotally a major proportion) admitted for other reasons but also found to test positive for COVID.  The BA.2 subvariant of Omicron is now dominant in over 40 countries, being more transmissible than the BA.1 but so far not causing more severe illness or more immune escape (sources: Airfinity, WHO).

The US mask mandate on aircraft and airports (as well as on buses and trains), was extended until at least April 18th

Hospitalisations for COVID-19 in UK have increased again, and in some European countries have stopped decreasing.  Total case numbers are increasing in some European countries but it is not clear whether this will translate to increased hospitalisations or deaths (source: Airfinity).   Causes of the increase in UK hospitalisations may include waning immunity, increased social mixing and the increase in BA.2 sublineage, as well as possibly a decrease in testing, and/or increased numbers of “incidental COVID” cases in people admitted for other reasons.  You will no doubt have read of the situation in Hong Kong, with high numbers of hospitalisations and deaths, in the face of quite low vaccination levels especially among elderly. 

Brief Notes:

This week there is a further downgrading of CDC alert levels in many locations, especially in Africa, but also in Philippines, Mexico, UAE and some others.
(The alert levels were raised to the highest levels for Hong Kong, Thailand, and New Zealand because of high and rising case numbers.) 

This commentary on travel measures from the London School of Hygiene and Tropical Medicine is interesting, and well worth reading – Kucharski et al:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(22)00366-X/fulltext

A very large nationwide French study looking at effectiveness of the Janssen vaccine compared with the Pfizer, was published by Botton et al: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2789572

“This study found that the Ad26.COV2.S [Janssen] vaccine is less effective against COVID-19–related hospitalization than the BNT162b2 [Pfizer] vaccine. These results strengthen the evidence supporting a second dose in people who received the [Janssen] vaccine by an mRNA vaccine as recommended in both France and the US.”

In the last update, I should have clarified that the Tartof article below related to pre-Omicron data.  The other studies referenced related to the Omicron period.

I omitted to include a reference from the UK Health Security Agency, which is an evidence review showing that the risk of long COVID is approximately halved by prior vaccination (and also somewhat reduced by vaccination AFTER infection). Protection was greater in older age groups: https://www.gov.uk/government/news/ukhsa-review-shows-vaccinated-less-likely-to-have-long-covid-than-unvaccinated

A new CDC report on waning of third dose – efficacy against emergency room attendance/hospitalisation declines from 87/91% (2 months) to 66/78% (four months). Ferdinands et al: https://www.cdc.gov/mmwr/volumes/71/wr/mm7107e2.htm This is consistent with earlier results from the UK Health Security Agency.

And a US study with several CDC authors, a case-control design looking at hospitalisation vs vaccination status, here – Lauring et al https://www.medrxiv.org/content/10.1101/2022.02.06.22270558v1 This showed that 2 doses of vaccine provided 65% effectiveness against hospitalisation with Omicron. However, 3 doses provided protection against hospitalisation with Omicron similar (86%) to that provided by 2 doses against Delta or Alpha (85%). It confirmed severity was higher for Delta, than Alpha, and lower for Omicron. In all cases, severity was lower amongst the vaccinated.

According, to the WHO, during the week of January 24 to January 30, the global number of new weekly cases remained stable with a 4% increase (over 22 million new cases) while deaths increased by 18% (over 59,000 new deaths reported).

In Africa there was a decrease in deaths, in Western Pacific no change but in other WHO regions (Americas, EMRO, Europe and Asia) deaths increased. Source: BlueDot.

Omicron now predominates in over 65 countries, with reduced vaccine effectiveness overall but still reasonably good vaccine protection against severe illness (see below).  There is evidence of the Omicron wave having reached its crest in a few locations, this having tended to occur 3-5 weeks after the beginning of the rapid rise.

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