Differences in protection from previous infection or vaccination against infection with Omicron BA.4/5 or BA.2

In a recent study posted to the medRxiv* preprint server, researchers investigated the differences in vaccination- and previous infection-induced immunities against the Omicron BA.2 and BA.4/5 subvariants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Study: 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 2022. Image Credit: Corona Borealis Studio/Shutterstock
Study: 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 2022. Image Credit: Corona Borealis Studio/Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Background

Since November 2021, the SARS-CoV-2 Omicron subvariants have increased the number of coronavirus disease 2019 (COVID-19) cases due to their increased transmissibility and immune evasion capabilities. The Netherlands experienced a surge in cases during the dominance of the BA.1 Omicron subvariant during late 2021, followed by subsequent BA.2, BA.4, and BA.5 dominance periods from early- to mid-2022.  

The Omicron subvariants have mutations in the spike protein residues, resulting in increased humoral immunity evasion. Studies have shown that the BA.4 and BA.5 subvariants exhibit the highest degree of neutralization escape, raising concerns about the recurrence of severe COVID-19 outcomes.

About the study

The present study examined the effect of vaccination- and prior infection-induced immune status on the occurrence of BA.2 and BA.4/5 between May and July 2022 — the transition phase between BA.2 and BA.4/5 predominance.

The researchers used SARS-CoV-2-positive test results from national community testing performed between 2 May to 24 July 2022 and carried out spike (S)-gene target failure (SGTF). The pseudonymized demographic and vaccination status information was also procured from the national community testing register.

The SGTF test was performed using TaqPath COVID-19 real-time polymerase chain reaction (RT-PCR). Combined with quantification cycles less than or equal to 30 to amplify the open reading frame 1 a and b (ORF1ab) and nucleocapsid (N) genes, the inability to detect the S-gene is a proxy for variants containing S 69/70 deletion, such as the Omicron subvariants BA.4 and BA.5. Samples that were non-SGTF were considered to be BA.2 positive, while SGTF samples were BA.4/5 since SGTF cannot distinguish between BA.4 and BA.5.

Whole genome sequencing (WGS) of random SGTF samples was also carried out to see the proportion of BA.4 to BA.5 samples. A combination of WGS and SGTF results from previous infections was used to determine the variants of previous SARS-CoV-2 infections. The immune status groups were defined according to vaccination history and prior infections. The BA.2 and BA.4/5 infections were correlated to these immune status groups using various statistical analyses.

Results

The results found that irrespective of vaccination status, the frequency of BA.4/5 cases was higher than BA.2 cases among individuals with previous infections, suggesting higher immune evasion by BA.4/5. BA.2 and BA.4/5 showed no association with vaccination status, implying that vaccines granted equal protection against all three subvariants.

Prior infection with the BA.1 subvariant presented lower and shorter protective effects against BA.4/5 than BA.2. The authors noted that a similar study from Denmark and other in vitro studies corroborated their results on BA.1 infection-induced immunity being ineffective against BA.4/5. They also discussed studies from the United Kingdom and Portugal, which substantiate their findings about similar vaccination-induced immunity against BA.2 and BA.4/5.

However, the authors believe that the evasion exhibited by BA.2 and BA.4/5 from prior infection-induced immunity is smaller than those seen for BA.1 or the Delta variant, which indicates high antibody escape between the earlier variants of concern than between Omicron subvariants.

The study had a few limitations. Based on the lack of confidence in the previous infection information, the authors believe some individuals might have been misclassified as not previously infected. Additionally, the BA.4 and BA.5 infections could not be separated for the entire dataset due to a lack of WGS data. Furthermore, the 90% threshold used for the TaqPath RT-PCR tests could have resulted in the misclassification of the subvariants. The authors believe, however, that these limitations are unlikely to change the results significantly.

Conclusion

To summarize, the study found that BA.4/5 exhibits higher antibody escape than BA.2 against immunity induced by previous infections from other subvariants such as BA.1, irrespective of vaccination status. Vaccination was seen to grant uniform protection against BA.2 and BA.4/5 infections.

The findings are significant as they suggest that vaccination provides better immunity against the Omicron subvariants than humoral immunity from previous infections. Therefore, vaccine updates and investigation of immune evasion by emergent subvariants should be prioritized.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Journal references:

Article Revisions

  • May 15 2023 - The preprint preliminary research paper that this article was based upon was accepted for publication in a peer-reviewed Scientific Journal. This article was edited accordingly to include a link to the final peer-reviewed paper, now shown in the sources section.
Dr. Chinta Sidharthan

Written by

Dr. Chinta Sidharthan

Chinta Sidharthan is a writer based in Bangalore, India. Her academic background is in evolutionary biology and genetics, and she has extensive experience in scientific research, teaching, science writing, and herpetology. Chinta holds a Ph.D. in evolutionary biology from the Indian Institute of Science and is passionate about science education, writing, animals, wildlife, and conservation. For her doctoral research, she explored the origins and diversification of blindsnakes in India, as a part of which she did extensive fieldwork in the jungles of southern India. She has received the Canadian Governor General’s bronze medal and Bangalore University gold medal for academic excellence and published her research in high-impact journals.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Sidharthan, Chinta. (2023, May 15). Differences in protection from previous infection or vaccination against infection with Omicron BA.4/5 or BA.2. News-Medical. Retrieved on November 02, 2024 from https://www.news-medical.net/news/20220927/Differences-in-protection-from-previous-infection-or-vaccination-against-infection-with-Omicron-BA45-or-BA2.aspx.

  • MLA

    Sidharthan, Chinta. "Differences in protection from previous infection or vaccination against infection with Omicron BA.4/5 or BA.2". News-Medical. 02 November 2024. <https://www.news-medical.net/news/20220927/Differences-in-protection-from-previous-infection-or-vaccination-against-infection-with-Omicron-BA45-or-BA2.aspx>.

  • Chicago

    Sidharthan, Chinta. "Differences in protection from previous infection or vaccination against infection with Omicron BA.4/5 or BA.2". News-Medical. https://www.news-medical.net/news/20220927/Differences-in-protection-from-previous-infection-or-vaccination-against-infection-with-Omicron-BA45-or-BA2.aspx. (accessed November 02, 2024).

  • Harvard

    Sidharthan, Chinta. 2023. Differences in protection from previous infection or vaccination against infection with Omicron BA.4/5 or BA.2. News-Medical, viewed 02 November 2024, https://www.news-medical.net/news/20220927/Differences-in-protection-from-previous-infection-or-vaccination-against-infection-with-Omicron-BA45-or-BA2.aspx.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Mild COVID-19 disrupts brain connectivity and reduces memory function in adolescents and young adults