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Omicron Reinfection Rate Higher Than Delta Variant, Study Finds

Omicron Reinfection Rate Higher Than Delta Variant, Study Finds

Recent studies on the latest COVID-19 variant have revealed alarming results. According to researchers, when compared to the delta variant, Omicron reinfection rate is higher. What exactly does this mean for those who are vaccinated? And are vaccines still effective against this variant?

Omicron Reinfection Rate: Higher Than Delta

Based on a report from Imperial College London, Omicron reinfection rate is 5.4 times higher than that of Delta1. This data was compiled by researchers based on persons who tested positive for Omicron.

For other variants, previous infections provided 85% protection. While it doesn’t offer full immunity, 85% is still a significant number and made outbreaks more manageable. In the case of Omicron however, this went down to as low as 19%. The higher Omicron reinfection rate also supports these findings.

In a South African study2, researchers found that the virus was able to evade the immunity provided by previous infections. With previous variants, none showed this degree of resilience and the ability to bypass immunity.

The worrying thing about Omicron is that reinfection is possible multiple times. In the case of health workers, this is very concerning since they have a higher exposure risk to COVID-19.

When it comes to severity of symptoms, there is no evidence that Omicron is less severe than Delta. But there is also currently no evidence that it is a more severe form of infection. Based on the limited information that we have, the reinfection rate is the biggest difference of Omicron compared to previous variants.

Are Vaccines Still Effective?

One of the pressing concerns that people have about Omicron is with regard to the effectiveness of vaccines. Since the possibility of reinfection is higher in Omicron, it’s possible that vaccines provide less protection for this variant.

According to a study from Duke University, the Moderna vaccine provides limited resistance to Omicron. In a statement, David Montefiori, a virologist who helped with the study, shares3, “The antibodies that people make after they get the standard two inoculations of the Moderna mRNA vaccine are 50 times less effective against omicron than they are against the original form of the virus.”

The study also reports that those who received a booster shot had increased protection against Omicron. With the booster shot, the effectiveness was about the same as with the Delta variant.

In a separate study from South Africa, the Pfizer vaccine had a 50% lower effectiveness against Omicron4. This marked a 30% decrease from the 80% protection against other variants. However, the researchers found that despite the drop, the vaccine still protected patients against severe symptoms of COVID-19.

Key Takeaways

Despite Omicron’s increased likelihood of causing reinfections, the current safety measures against infection still prove to be effective. Getting vaccinated is still the best line of defense against infection, and getting a booster shot as soon as possible can help strengthen immunity against Omicron5.

Aside from the vaccine, it’s also important for people to wear masks and practice social distancing. Just because you’ve already had the vaccine or have been previously infected doesn’t mean you can skip these precautionary measures. Previously infected people can still be carriers since the Omicron reinfection rate is high.

As much as possible, try to stay at home and avoid crowded places. If you do need to go outside, keep away from crowds and practice the standard safety precautions. So long as we do our part and follow these measures, we can lower the chances that we can get infected by Omicron or other COVID-19 variants.

At the end of the day, we need to be extra vigilant since the pandemic is still ongoing. We can lower the risk of infection by following safety measures and getting the vaccine.

Learn more about Coronavirus here.

Hello Health Group does not provide medical advice, diagnosis or treatment.


1 Omicron largely evades immunity from past infection or two vaccine doses | Imperial News | Imperial College London, https://www.imperial.ac.uk/news/232698/omicron-largely-evades-immunity-from-past/, Accessed December 20, 2021

2 Increased risk of SARS-CoV-2 reinfection associated with emergence of the Omicron variant in South Africa | medRxiv, https://www.medrxiv.org/content/10.1101/2021.11.11.21266068v2, Accessed December 20, 2021

3 Moderna vaccine no match for omicron except with booster, study finds : Shots – Health News : NPR, https://www.npr.org/sections/health-shots/2021/12/15/1064202754/omicron-evades-moderna-vaccine-too-study-suggests-but-boosters-help, Accessed December 20, 2021

4 Omicron response to vaccines analyzed in new study from South Africa : Goats and Soda : NPR, https://www.npr.org/sections/goatsandsoda/2021/12/14/1063947940/vaccine-protection-vs-omicron-infection-may-drop-to-30-but-does-cut-severe-disea, Accessed December 20, 2021

5 Omicron Variant: What You Need to Know | CDC, https://www.cdc.gov/coronavirus/2019-ncov/variants/omicron-variant.html, Accessed December 20, 2021

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Written by Jan Alwyn Batara Updated Dec 21, 2021
Fact Checked by Vincent Sales