欧州連合の専門機関たる欧州疾病予防管理センターからオミクロン株に対するワクチンの効果が実質的にマイナスだという非常に残念なお知らせ

 

Interim analysis of COVID-19 vaccine effectiveness in healthcare workers, an ECDC multi-country study, May 2021–July 2022

Monitoring

21 Nov 2022

This document reports on one of ECDC’s multi-country studies in the hospital setting to measure product-specific COVID-19 VE against any laboratory-confirmed SARS-CoV-2 infection among healthcare workers (HCWs) eligible for vaccination.

Executive summary

ECDC is building infrastructure to allow the regular monitoring of COVID-19 vaccine effectiveness (VE) over time, using a multi-country approach that involves studies implemented in different settings [1,2].

As of July 2022, 16 hospital sites (in Croatia, Estonia, Greece, Ireland, Italy, Latvia, Poland, Portugal, and Spain) have participated in the study, covering the period from 3 May 2021 to 19 July 2022. In this period, the study teams approached 2 832 HCWs, enrolled 2 629 of them, and followed up with 2 369 . Aside from 18 HCWs who remained unvaccinated during the study period, all other HCWs recruited to date have been vaccinated with one or more doses of COVID-19 vaccines at enrolment. Nearly two thirds (64%) of them have received a booster dose.

At enrolment, over a quarter (26%) of the HCWs reported having had a COVID-19 infection, of which the majority (87%) were diagnosed 46 or more days prior to enrolment. Serological results have been reported by 11 sites, of which all reported detection of anti-spike antibodies in >90% of HCWs at enrolment.

Genetic sequencing data for breakthrough infections have been submitted for 176 HCWs from eight sites, of which 116 were Omicron variant infections (B.1.1529) isolated since 15 December 2021. Thirty were Delta variant infections isolated between May 2021 and January 2022.

Omicron variant BA.1 was isolated until May 2022, when it was replaced by BA.2, which was subsequently replaced in June 2022 by BA.4/5.

Among HCWs who had received only the primary vaccination schedule, 196 SARS-CoV-2 infections were reported, representing a cumulative incidence of 2.9 per 1 000 person days, and 257 SARS-CoV-2 infections were reported among those who had a received a booster dose, representing a cumulative incidence of 2.7 per 1 000 person days.

The adjusted rVE was 7% (95%CI: -28% to 32%) overall, while the adjusted rVE was 11% (95%CI: -48% to 47%) in the HCWs reporting a previous COVID-19 episode before enrolment and -6% (95%CI -81% to 38%) in HCWs without a previous COVID-19 episode.

These results are in line with published evidence indicating that current COVID-19 vaccines have low effectiveness against mild Omicron infections, including after a booster dose. While this analysis does not include VE against severe disease, published literature indicates that VE against severe disease due to the Omicron variant is high following the administration of both the primary course and further maintained by a booster dose. Although point estimates of VE indicated some protective effects, the wide confidence intervals make the interpretation of the results difficult. The precision of the rVE estimates may improve through the continuation of the study in the participating sites (longer follow-up) or through the recruitment of new sites to increase the size of the HCW cohort.

https://www.ecdc.europa.eu/en/publications-data/interim-analysis-covid-19-vaccine-effectiveness-healthcare-workers-ecdc-multi

自然感染回復で得られる免疫無しでのワクチン接種のみの効果

＝マイナス６% (95%CI -81% to 38%)

結局、ワクチンで新型コロナの感染や死亡はどれぐらい防げるの？　国内外で示されるワクチン効果

11/17(木) 11:04配信

オミクロンに置き換わった今、研究結果を当てはめられるか？

――今はオミクロンに置き換わっているので、デルタ株へのワクチン効果を見たこの研究を現状に当てはめることはできないじゃないかと指摘されそうな気もします。それに対してはどう答えますか？ ご指摘の通りのところはあります。この研究では、あくまでもデルタ株流行までに関する効果を見ているので、オミクロン株に対するワクチンの効果や免疫の減弱を考えると、感染や死亡を防ぐ効果はもっと少なくなることも考えられます。 ただ、ワクチン効果はマイナスにはなりません。さらにブースター接種が始まっているので、落ちた免疫を上げる効果がまた考えられます。 人口レベルで免疫を保持している人の割合が減っていく中で、ブースター接種によってまた感染・死亡リスクが下がる。しかし、オミクロンや、オミクロンの亜系統が出てきて、ワクチンの効果は変化していく。 ですので、免疫の様相が非常に複雑になっていることは間違いないです。 ――ワクチンの効果がそういう変化で減るとしても、感染や死亡を減らす傾向にあるのは変わらないですよね？ 流行規模はどんどん大きくなっていますし、人口レベルで見た場合、ワクチンの効果が落ちたとしても感染や死亡を予防する数は決して無視できないレベルになっていると思います。 ――それを考えると、ワクチンの影響はむしろ大きくなっているかもしれないですか？ 大きくなっている可能性もあります。流行サイズが大きくなると、それに伴ってワクチンによる効果も大きくなるからです。 ただ、今は感染によって免疫を持っている人も多数います。ワクチン接種者とワクチン未接種者それぞれの中に感染で免疫を得ている人がいるわけです。 この論文ではまだ感染を経験した人々が少なかったので、その割合を考慮はしなかったのですが、今後、同様の研究をする際にはより慎重に評価をする必要があります。 オミクロン株で感染した人が増えた今は、自然感染を経験した人々も考慮しなければいけない要素になりそうです。

https://news.yahoo.co.jp/articles/782c04d727a76c79c46a87b9cb6a9be3c1b6411d?page=5

 なあに、それでも勇者様ならきっと迷わず接種し続けてくれる！（爆ｗｗｗｗｗｗｗｗｗｗｗ