Eurosurv. Higher risk of SARS-CoV-2 Omicron BA.4/5 infection than of BA.2 infection after previous BA.1 infection, the Netherlands, 2 May to 24 July 2

[tetano]

• Stijn P Andeweg[SUP]1[/SUP] , Brechje de Gier[SUP]1[/SUP] , Harry Vennema[SUP]1[/SUP] , Ivo van Walle[SUP]1[/SUP] , Noortje van Maarseveen[SUP]2,3[/SUP] , Nina E Kusters[SUP]3[/SUP] , Hester E de Melker[SUP]1[/SUP] , Susan JM Hahné[SUP]1[/SUP] , Susan van den Hof[SUP]1[/SUP] , Dirk Eggink[SUP]1,*[/SUP] , Mirjam J Knol[SUP]1,*[/SUP]

Background

In summer 2022, SARS-CoV-2 Omicron BA.5 became dominant in Europe. In vitro studies have shown a large reduction of antibody neutralisation for this variant.

Aim

We aimed to investigate differences in protection from previous infection and/or vaccination against infection with Omicron BA.4/5 vs BA.2.

Methods

We employed a case-only approach including positive PCR tests from community testing between 2 May and 24 July 2022 that were tested for S gene target failure (SGTF), which distinguishes BA.4/5 from BA.2 infection. Previous infections were categorised by variant using whole genome sequencing or SGTF. We estimated by logistic regression the association of SGTF with vaccination and/or previous infection, and of SGTF of the current infection with the variant of the previous infection, adjusting for testing week, age group and sex.

Results

The percentage of registered previous SARS-CoV-2 infections was higher among 19,836 persons infected with Omicron BA.4/5 than among 7,052 persons infected with BA.2 (31.3% vs 20.0%). Adjusting for testing week, age group and sex, the adjusted odds ratio (aOR) was 1.4 (95% CI: 1.3–1.5). The distribution of vaccination status did not differ for BA.4/5 vs BA.2 infections (aOR = 1.1 for primary and booster vaccination). Among persons with a previous infection, those currently infected with BA4/5 had a shorter interval between infections, and the previous infection was more often caused by BA.1, compared with those currently infected with BA.2 (aOR = 1.9; 95% CI: 1.5–2.6).

Conclusion

Our results suggest immunity induced by BA.1 is less effective against BA.4/5 infection than against BA.2 infection.






https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.7.2200724#html_fulltext