28 juli 2022: Bron: Nature

Uit nieuwe studies blijkt natuurlijke immuniteit opgelopen door een besmetting met de Omicron variant van het coronavirus - Covid-19 voor een veel betere bescherming tegen een herinfectie door de BA-4 en BA-5 varianten te zorgen dan een van de gebruikte vaccins of boosters tegen de oorspronkelijke mutaties van het Covid-19 virus.

De onderzoekers ontdekten dat infectie met een pre-Omicron-variant herinfectie met BA.4 of BA.5 voorkwam met een effectiviteit van 28,3%, en symptomatische herinfectie met beide subvarianten met een effectiviteit van 15,1%. Eerdere infectie met Omicron gaf een veel sterkere bescherming: het was 79,7% effectief bij het voorkomen van herinfectie met BA.4 en BA.5 en 76,1% bij het voorkomen van symptomatische herinfectie. 

Dit meldt Nature op basis van twee studies. 


  1. Altarawneh, H. N. et al. Preprint at medRxiv https://doi.org/10.1101/2022.07.11.22277448 (2022).

  2. Chemaitelly, H. et al. Preprint at medRxiv https://doi.org/10.1101/2022.07.06.22277306 (2022).

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Hier het persbericht van Nature: 

Prior Omicron infection protects against BA.4 and BA.5 variants

The Omicron BA.4 and BA.5 subvariants of SARS-CoV-2 have proven to be stealthier at evading people’s immune defences than all of their predecessors.

But recent research shows that previous infection with an older variant (such as Alpha, Beta or Delta) offers some protection against reinfection with BA.4 or BA.5, and that a prior Omicron infection is substantially more effective. That was the conclusion of a study that evaluated all of Qatar’s COVID-19 cases since the wave of BA.4 and BA.5 infections began1.

The work, which was posted on the medRxiv preprint server on 12 July and has not yet been peer reviewed, feeds into broader research on “how different immunities combine with each other”, says study co-author Laith Abu-Raddad, an infectious-disease epidemiologist at Weill Cornell Medicine-Qatar in Doha.

Everyone has a different immune history, because people have received different combinations of COVID-19 vaccines and been infected with assorted variants during the course of the pandemic. “Different histories equip people with different immunity against upcoming infection,” says Abu-Raddad. Knowing how these diverse immune responses interact inside a person will be “very important for the future of the pandemic”, he adds.

Natural immunity

To see how much protection previous infection offers against the two Omicron subvariants, Abu-Raddad and colleagues analysed COVID-19 cases recorded in Qatar between 7 May this year — when BA.4 and BA.5 first entered the country — and 4 July. They looked at the number of people known to have been infected previously who tested positive or negative for COVID-19, and identified which infections were caused by BA.4 or BA.5 by examining positive test samples to see whether they contained a specific gene mutation.

The researchers found that infection with a pre-Omicron variant prevented reinfection with BA.4 or BA.5 with an effectiveness of 28.3%, and prevented symptomatic reinfection with either subvariant with an effectiveness of 15.1%. Prior infection with Omicron granted stronger protection: it was 79.7% effective at preventing BA.4 and BA.5 reinfection and 76.1% effective at preventing symptomatic reinfection.

Although it seems counterintuitive to see stronger protection against any reinfection than symptomatic reinfection, the researchers say this effect is in line with previous studies and is probably caused by the estimates having wide confidence intervals.>>>>>>>>reed more

De laatste onderzoek is nog niet peer reviewed maar hier wel al het abstract met de studiegegevens:

Protection of SARS-CoV-2 natural infection against reinfection with the Omicron BA.4 or BA.5 subvariants

Heba N. AltarawnehHiam ChemaitellyHoussein H. AyoubMohammad R. HasanPeter CoyleHadi M. YassineHebah A. Al-KhatibFatiha M. BenslimaneZaina Al-KanaaniEinas Al-KuwariAndrew JeremijenkoAnvar Hassan KaleeckalAli Nizar LatifRiyazuddin Mohammad ShaikHanan F. Abdul-RahimGheyath K. NasrallahMohamed Ghaith Al-KuwariAdeel A. ButtHamad Eid Al-RomaihiMohamed H. Al-ThaniAbdullatif Al-KhalRoberto BertolliniPatrick TangLaith J. Abu-Raddad


This study estimates the effectiveness of previous infection with SARS-CoV-2 in preventing reinfection with Omicron BA.4/BA.5 subvariants using a test-negative, case–control study design. Cases (SARS-CoV-2-positive test results) and controls (SARS-CoV-2-negative test results) were matched according to sex, 10-year age group, nationality, comorbid condition count, calendar week of testing, method of testing, and reason for testing. Effectiveness was estimated using the S-gene “target failure” (SGTF) infections between May 7, 2022-July 4, 2022. SGTF status provides a proxy for BA.4/BA.5 infections, considering the negligible incidence of other SGTF variants during the study. Effectiveness was also estimated using all diagnosed infections between June 8, 2022-July 4, 2022, when BA.4/BA.5 dominated incidence. Effectiveness of a previous pre-Omicron infection against symptomatic BA.4/BA.5 reinfection was 15.1% (95% CI: -47.1-50.9%), and against any BA.4/BA.5 reinfection irrespective of symptoms was 28.3% (95% CI: 11.4-41.9%). Effectiveness of a previous Omicron infection against symptomatic BA.4/BA.5 reinfection was 76.1% (95% CI: 54.9-87.3%), and against any BA.4/BA.5 reinfection was 79.7% (95% CI: 74.3-83.9%). Results using all diagnosed infections when BA.4/BA.5 dominated incidence confirmed the same findings. Sensitivity analyses adjusting for vaccination status confirmed study results. Protection of a previous infection against BA.4/BA.5 reinfection was modest when the previous infection involved a pre-Omicron variant, but strong when the previous infection involved the Omicron BA.1 or BA.2 subvariants. Protection of a previous infection against BA.4/BA.5 was lower than that against BA.1/BA.2, consistent with BA.4/BA.5’s greater capacity for immune-system evasion than that of BA.1/BA.2.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

The authors are grateful for institutional salary support from the Biomedical Research Program and the Biostatistics, Epidemiology, and Biomathematics Research Core, both at Weill Cornell Medicine-Qatar, as well as for institutional salary support provided by the Ministry of Public Health, Hamad Medical Corporation, and Sidra Medicine. The authors are also grateful for the Qatar Genome Programme and Qatar University Biomedical Research Center for institutional support for the reagents needed for the viral genome sequencing. The funders of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the article. Statements made herein are solely the responsibility of the authors.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.


The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study was approved by the Hamad Medical Corporation and Weill Cornell Medicine-Qatar Institutional Review Boards with waiver of informed consent.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.


I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).


I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.


Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv

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