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Post infection immunity, good news

Bywebmaster

Nov 22, 2024



Journal of Infection

https://www.journalofinfection.com/action/showPdf?pii=S0163-4453%2820%2930781-7

Pre-proof, accepted manuscript

Main points

Whether SARS-CoV-2 infection confers immunity to reinfection is uncertain

The ‘second wave’ of transmission offered an opportunity to examine this

We observed no symptomatic reinfections in a cohort of healthcare workers

This apparent immunity to re-infection was maintained for at least 6 months

Further studies are required to define immunological mechanism(s) and durability

Also

Immunity to seasonal coronaviruses is (probably) maintained for up to 12 months

The study

N = 11,103 healthcare workers, documented evidence of previous infection status

First wave

March to April 2020

Second wave

October to November 2020

Newcastle and North Tyne

RT-PCR testing, all HCWs with symptoms, since early March 2020

Extensive IgG antibody testing, 937 / 11,103

Infected group

N = 1,038, with evidence of previous infection (positive PCR and/or Ab)

Non infected group

N = 10,137 without (negative Ab, without positive PCR)

Endpoint analysis, symptomatic SARS-CoV-2 infection

Up to 20th Nov 2020

2,243 HCWs underwent PCR testing for symptoms

128 had previous confirmed SARS-CoV-2 infection

2,115 had not had previous infection

In those previously infected, median of 173 (IQR: 162-229) days from first positive PCR/antibody result

Previous infection group

Test positivity rates, 0% (0 out of 128)

No previous infection group

Test positivity rates, 13.7% (290 out of 2,115)

(less than 0.0001 2 test)

One in 10,000
Asymptomatic PCR screening

N = 481 HCWs

With past infection

N = 106

Positivity rate = 0% (0 out of 106)

Without past infection

N = 375

Positivity rate = 5.9% (22 out of 375)

Conclusion

Immunity is maintained for at least 6 months

Infection appears to result in protection against symptomatic infection in working age adults, at least in the short term.

This is consistent with

The low rates of reinfection reported in the literature

The reported ability of vaccines to protect with high efficacy against symptomatic SARS-CoV-2

Source

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