# Is having Covid previously as good a protection as full vaccination?

**URL:** <https://boards.straightdope.com/t/is-having-covid-previously-as-good-a-protection-as-full-vaccination/949405>\
**Category:** The Quarantine Zone\
**Tags:** covid-quarantine\
**Created:** [August 24, 2021, 12:30am UTC](https://boards.straightdope.com/t/is-having-covid-previously-as-good-a-protection-as-full-vaccination/949405 "2021-08-24T00:30:32Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![Trom](https://avatars.discourse-cdn.com/v4/letter/t/958977/32.png) [@Trom](https://boards.straightdope.com/u/Trom)\
**Post date:** [August 26, 2021, 4:48pm UTC](https://boards.straightdope.com/t/is-having-covid-previously-as-good-a-protection-as-full-vaccination/949405/5 "2021-08-26T16:48:37Z")

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Here’s a [study from Israel](https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1) ([full pdf](https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1.full.pdf)) looking at reinfections across three groups:

- vaccinated (Pfizer) and no previous infection
- non-vaccinated and confirmed previous infection
- vaccinated and confirmed previous infection

The study looks at the time period where the Delta variant was dominant in Israel.

> This is the largest real-world observational study comparing natural immunity, gained  
> through previous SARS-CoV-2 infection, to vaccine-induced immunity, afforded by  
> the BNT162b2 mRNA vaccine.

**Results**

> SARS-CoV-2-naïve vaccinees had a 13.06-fold (95% CI, 8.08 to 21.11) increased risk  
> for breakthrough infection with the Delta variant compared to those previously  
> infected, when the first event (infection or vaccination) occurred during January and  
> February of 2021. The increased risk was significant (P\<0.001) for symptomatic  
> disease as well. When allowing the infection to occur at any time before vaccination  
> (from March 2020 to February 2021), evidence of waning natural immunity was  
> demonstrated, though SARS-CoV-2 naïve vaccinees had a 5.96-fold (95% CI, 4.85 to 7.33) increased risk for breakthrough infection and a 7.13-fold (95% CI, 5.51 to 9.21)  
> increased risk for symptomatic disease. SARS-CoV-2-naïve vaccinees were also at a  
> greater risk for COVID-19-related-hospitalizations compared to those that were  
> previously infected.

Some of the raw numbers:

46,035 persons in each of the groups (previously infected vs.  
vaccinated

> When comparing the vaccinated individuals to those previously infected at any time  
> (including during 2020), we found that throughout the follow-up period, 748 cases of  
> SARS-CoV-2 infection were recorded, 640 of which were in the vaccinated group  
> (breakthrough infections) and 108 in the previously infected group (reinfections)

> 552 symptomatic cases of SARS-CoV-2 were recorded, 484 in the vaccinated group and 68 in the previously infected group

> COVID-19 related hospitalizations occurred in 21 and 4 of the breakthrough infection and reinfection groups, respectively

> No COVID-19-related deaths were recorded

**Conclusions**

> This study demonstrated that natural immunity confers longer lasting and stronger protection against infection, symptomatic disease and hospitalization caused by the Delta variant of SARS-CoV-2, compared to the BNT162b2 two-dose vaccine-induced immunity. Individuals who were both previously infected with SARS-CoV-2 and given a single dose of the vaccine gained additional protection against the Delta variant.

My thoughts: This is absolutely fantastic news. **The vaccines are outstanding, and strong natural immunity takes nothing away from that.** We should all be hoping for strong and lasting natural immunity, especially given the number of natural infections out there.

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