[D66] ECDC voorziet zomerse coronagolf; Nederland opnieuw niet voorbereid (Wuhan Coronavirus 2019-nCoV #906)

[Dr. Marc-Alexander Fluks]

Bron:  European Centre for Disease Prevention and Control (ECDC)
Datum: 13 mei 2022
URL:   
https://www.ecdc.europa.eu/en/news-events/epidemiological-update-sars-cov-2-omicron-sub-lineages-ba4-and-ba5
Ref:   
https://www.telegraaf.nl/nieuws/1841487176/nieuwe-mutaties-zorgen-voor-zomergolf-corona
Opm:   De NOS meldt zojuist dat Nederland slecht op een herfst-
        coronagolf zou zijn voorbereid. Ons land loopt nog steeds
        achter de feiten aan (zelfs als men er op voorbereid zou
        kunnen zijn, zoals thans het geval zij),
        
https://nos.nl/artikel/2429004-door-uitblijven-coronastrategie-komt-lockdown-weer-in-beeld
Opm:   Vandaag spreekt de Tweede Kamer over het 'langere termijn
        coronabeleid' (10:00-18:00)
        
https://www.tweedekamer.nl/debat_en_vergadering/commissievergaderingen/details?id=2022A02396
        
https://www.tweedekamer.nl/vergaderingen/livedebat/suze-groenewegzaal


Epidemiological update: SARS-CoV-2 Omicron sub-lineages BA.4 and BA.5
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As of 12 May 2022, ECDC has reclassified Omicron sub-lineages BA.4 and 
BA.5 from variants of interest to variants of concern.

BA.4 and BA.5 were first detected in South Africa in January and 
February 2022, respectively, and since then they have become the 
dominant variants there. Both lineages contain the amino-acid 
substitutions L452R, F486V, and R493Q in the spike receptor binding 
domain compared to BA.2. Preliminary studies suggest a significant 
change in antigenic properties of BA.4 and BA.5 compared to BA.1 and 
BA.2, especially compared to BA.1. Additionally, there is an increasing 
trend in the variant proportions for BA.5 observed in Portugal the 
recent weeks, accompanied by an increase in COVID-19 case numbers and 
test positivity rate.

The Portuguese National Institute of Health estimated that BA.5 already 
accounted for ~37% of the positive cases as of 8 May 2022. The estimated 
daily growth advantage for BA.5 over BA.2 is 13%, which is similar to 
the 12% daily growth advantage previously reported by South Africa. 
Assuming such growth rate, BA.5 will become the dominant variant in 
Portugal by 22 May 2022.

The currently observed growth advantage for BA.4 and BA.5 is likely due 
to their ability to evade immune protection induced by prior infection 
and/or vaccination, particularly if this has waned over time. Limited 
available data from in vitro studies evaluating sera from unvaccinated 
individuals who have experienced a prior BA.1 infection indicate that 
both BA.4 and BA.5 are capable of escaping immune protection induced by 
infection with BA.1. Such unvaccinated individuals are unlikely to be 
protected against symptomatic infection with BA.4 or BA.5. Whilst sera 
from vaccinated individuals performed better in invitro studies done 
thus far, protection derived from currently available vaccines does wane 
over time against the Omicron variant.

There is currently no indication of any change in severity for BA.4/BA.5 
compared to previous Omicron lineages.

Taken together, this indicates that the presence of these variants could 
cause a significant overall increase in COVID-19 cases in the EU/EEA in 
the coming weeks and months. The overall proportion of BA.4 and BA.5 in 
the EU/EEA is currently low but the high growth advantages reported 
suggest that these variants will become dominant in the EU/EEA in the 
coming months. Based on the limited data currently available, no 
significant increase in infection severity compared to the circulating 
lineages BA.1 and BA.2 is expected. However, as in previous waves, if 
COVID-19 case numbers increase substantially, some level of increased 
hospital and ICU admissions is likely to follow.

ECDC encourages countries to remain vigilant for signals of BA.4 and 
BA.5 emergence. Early variant detection critically relies on sensitive 
and representative testing and genomic surveillance, with timely 
sequence reporting. Representative testing policies are required to 
reliably estimate the contribution of these variants to ongoing viral 
circulation, as well as to accurately determine the extent these 
variants may contribute to any observed increases in severe outcomes in 
the population, such as increases in hospital or ICU admissions.

The public health benefit of administering a second mRNA COVID-19 
booster dose was recently assessed by ECDC to be clearest in those aged 
80 years and above and immediate administration of a second booster dose 
in this population was found to be optimal in situations of continued 
high or increasing viral circulation.

Continued close epidemiological and vaccine effectiveness monitoring is 
essential in order to rapidly detect signals of increased SARS-CoV-2 
circulation or risk of severe disease among vaccinated individuals. If 
such signals emerge, a second booster may be considered for some or all 
adults 60 years and older and for other vulnerable groups. Countries 
should have plans in place for the rapid deployment of booster doses in 
these population groups.

For all age groups, it remains a priority to improve COVID-19 vaccine 
uptake of the primary course and first booster dose in populations who 
have yet to receive them.

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(c) 2022 ECDC