Since the last update around 10 days ago, we have seen US President Biden announced his view that the pandemic was over, although adding that we are still contending with the problem of COVID-19. At the time the US death rate was running at 400 per day, around 3-4x more than the typical average for influenza. Others including leaders of WHO have responded saying that it is not over but the trend is in that direction. In essence they are expressing the same observation, that we are on the journey from emergency to a more stable situation of an established virus with ongoing evolution. The WHO Emergency Committee on COVID-19 (which considers its classification as a Public Health Emergency of International Concern) will meet again on 13 October.
Some commentary on variants and sub-variants, drawn principally from BlueDot and Airfinity: Variants continue to evolve and there are a number of countries, notably in Europe, seeing an upturn in case numbers and hospitalisations. Currently, it is unclear which variant may be the predominant strain circulating over the next few months, and how effective the updated boosters may be at mitigating impacts. BA.4.6 shows some signs of outperforming BA.5 (with an additional spike protein mutation) but is considered unlikely to cause a wave of infections because of lacking certain spike mutations.
Meanwhile a study showed BA.2.75.2 to have the most extensive immune escape of studied variants. The number of BA.2.75.2 cases is still very small across the globe, but counts are doubling every week. If this growth rate was to continue, BA.2.75.2 could cause a much anticipated winter wave. There are other sub-lineages with potential to increase, and there is also some evolutionary convergence of specific mutations that confer immune evasion advantages (such as R346T), meaning that different pathways of evolution are leading towards similar sub-lineages. There are others with potential to compete besides the two mentioned above. Converging evolution may eventually lead to improved cross-protection of variant-specific boosters and/or infections against future variants.
There is also the possibility of a non-Omicron lineage emerging, as is the possibility of a strain causing more severe disease. High uptake of booster vaccinations, improving coverage of primary series and using mitigations to reduce transmission all remain critically important to blunt the population-level impacts of COVID-19.
On vaccine effectiveness with and without infection, a detailed study from North Carolina with some CDC input was published by Lin et al in JAMA: https://jamanetwork.com/journals/jama/fullarticle/2796893
The paper looks at immunity, over time, from various vaccines (Pfizer, Moderna, AstraZeneca), with or without prior infection, against different outcomes. Quoting from the discussion:
“The findings from this study suggest that the estimated effectiveness of all 3 vaccines was high, especially against hospitalization and death, although the effectiveness decreased over time. After the emergence of the Omicron variant, the estimated vaccine effectiveness was lower against infection, but estimated effectiveness against hospitalization and death remained high. Previous SARS-CoV-2 infection was associated with lower risks of infection, hospitalization, and death. How-ever, the protection waned over time, especially against the outcome of infection, and the risk of reinfection with Omicron became appreciable after 4 months. Boosting for previously uninfected persons was associated with protection, especially against hospitalization and death, while boosting also was associated with additional protection to previously infected individuals.”
As was mentioned in the last update, there are similar findings from another papers (for example see Kelly et al https://jamanetwork.com/journals/jama/fullarticle/2796892 and
Ridgway et al: https://jamanetwork.com/journals/jama/fullarticle/2796847) but Lin et al above is a comprehensive analysis. There is an accompanying editorial from Tenforde of CDC which is recommended reading: https://jamanetwork.com/journals/jama/fullarticle/2796894 Overall, it continues to appear that a combination of vaccinations and recurrent infections confers high levels of protection against severe illness (hybrid immunity).
I recommend you look at a very interesting report released in Canada by a group of doctors looking at the effectiveness of travel restrictions, with the benefit of hindsight and with a view to the future, here: https://www.newswire.ca/news-releases/infectious-disease-and-medical-experts-declare-federal-government-travel-restrictions-ineffective-at-protecting-canadians-from-covid-19-spread-813481354.html - As this article appears, Canada’s requirement for masks on board, and for visitors to be vaccinated against COVID-19, are all being lifted on 1 October.
On mortality, a CDC study by Adjei et al: https://www.cdc.gov/mmwr/volumes/71/wr/mm7137a4.htm?s_cid=mm7137a4_w was published concluding that the case mortality ratio among patients hospitalized primarily for COVID-19 was 15.1 during the Delta, 13.1 during the early Omicron, and 4.9 during the later Omicron periods (Table 2).
A paper from Israel looked at evidence for protection from vaccination against long COVID - Kuodi et al: Association between BNT162b2 vaccination and reported incidence of post-COVID-19 symptoms: cross-sectional study 2020-21, Israel | npj Vaccines (nature.com) - Those who received two vaccine doses were less likely than unvaccinated individuals to report any of the most frequently reported long COVID symptoms (fatigue, headache, weakness of limbs, and persistent muscle pain) by 62%, 50%, 62%, and 66% respectively,
This Danish household transmission analysis (pre-print) concludes that the extra transmission of Omicron compared with Delta is based primarily on immune evasion, more than pure increased transmissibility – Lyngse et al: https://www.medrxiv.org/content/10.1101/2022.09.19.22280095v1 - This is consistent with the findings from a peer-reviewed Norwegian household transmission study, Jalali et al: https://www.nature.com/articles/s41467-022-33233-9#Ack1
Antibodies as possible causes for vaccine-related myocarditis are discussed here by Thurner et al from Germany: https://www.nejm.org/doi/full/10.1056/NEJMc2205667
Another article on long term follow up of those with vaccine-related myocarditis is here, with CDC input – Kracalik et al: https://www.thelancet.com/journals/lanchi/article/PIIS2352-4642(22)00244-9/fulltext
The triennial ICAO Assembly has been taking place this week in Montreal, and there is a major focus on pandemic preparedness and response with respect to aviation and travel.
Monkeypox vaccine eligibility has been expanded in the US, moving to a strategy of pre-exposure prophylaxis – which has been permitted by increased vaccine supply. Eligibility is based on higher-risk sexual contacts or recent sexually transmitted infections. (Source: Airfinity).
There is a WHO “EPI-WIN” seminar on monkeypox and any implications for travel, next week on October 5th (at 1300 Central European Time). The link is here: EPI-WIN YouTube channel.
On the question of Ebola, you will probably have heard news of the new outbreak in Uganda where there are now 36 cases (18 probable, 18 confirmed) including 23 deaths. The outbreak is of the Sudan version (known as Sudan virus) rather than the Zaire version responsible for the recent DRC outbreaks, and this is significant because, whereas an Ebola vaccine has been successfully used in DRC, there are no licensed vaccines or therapeutics for use against the Sudan version. The disease is a haemorrhagic fever, with a very high case fatality rate; it originates in animal species and is spread between humans by close contact through blood and body fluids - usually within households and also through handling of bodies during funerals (Source: WHO).
Best wishes,
David Powell
IATA Medical Advisor