Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

/.../The duration of immunity resulting from natural infection, although not well understood, is suspected to persist for ≥90 days in most persons.

/.../ For example, a recent laboratory study found that sera collected from previously infected persons before they were vaccinated provided a relatively weaker, and in some cases absent, neutralization response to the B.1.351 (Beta) variant when compared with the original Wuhan-Hu-1 strain (1)

Sex månader efter genomgången covid-19 fanns inga tecken på aktiv hjärnskada hos de hundra patienter som ingick i en studie från Göteborgs universitet. Detta oavsett hur svårt sjuka de varit, eller kvarstående neurologiska symtom. Resultaten tyder på att så kallad postcovid inte beror på fortgående skador på centrala nervsystemet.

Påverkan på centrala nervsystemet, CNS, och tecken på hjärnskada har beskrivits sedan början av SARS-CoV-2-pandemin. Forskarna bakom den nu aktuella studien har tidigare, genom att mäta en blodbaserad biomarkör för hjärnskada, visat att inlagda patienter som fick syrgasbehandling eller intensivvård ofta hade tecken på hjärnskada.

På senare tid har det dessutom blivit allt tydligare att många patienter lider av kvarstående neurologiska komplikationer efter den akuta fasen av covid-19. I begreppet postcovid ingår bland annat apati, trötthet och nedsatt kognitiv funktion.

Det är lugnande att de förhöjda koncentrationerna av markörer för hjärnskada återgår till det normala tre till sex månader efter den akuta fasen av covid-19, vilket tyder på att det inte finns någon kvarstående hjärnskada och att det finns god chans till återhämtning även för patienter med fortsatta postakuta neurologiska och kognitiva symtom, säger Gisslén.

/.../The new study was based on 246 Kentucky adults who were reinfected in May and June this year after previously being infected in 2020.

They were compared with 492 “controls” who were matched by sex, age, and time of initial positive test.

The analysis found that unvaccinated people were 2.34 times as likely to be reinfected compared to people fully vaccinated with the Pfizer, Moderna or Johnson & Johnson vaccines.

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Discussion

This study found that among Kentucky residents who were previously infected with SARS-CoV-2 in 2020, those who were unvaccinated against COVID-19 had significantly higher likelihood of reinfection during May and June 2021. This finding supports the CDC recommendation that all eligible persons be offered COVID-19 vaccination, regardless of previous SARS-CoV-2 infection status.

Reinfection with SARS-CoV-2 has been documented, but the scientific understanding of natural infection-derived immunity is still emerging (5). The duration of immunity resulting from natural infection, although not well understood, is suspected to persist for ≥90 days in most persons.** The emergence of new variants might affect the duration of infection-acquired immunity, and laboratory studies have shown that sera from previously infected persons might offer weak or inconsistent responses against several variants of concern (2,6). For example, a recent laboratory study found that sera collected from previously infected persons before they were vaccinated provided a relatively weaker, and in some cases absent, neutralization response to the B.1.351 (Beta) variant when compared with the original Wuhan-Hu-1 strain (1). Sera from the same persons after vaccination showed a heightened neutralization response to the Beta variant, suggesting that vaccination enhances the immune response even to a variant to which the infected person had not been previously exposed. Although such laboratory evidence continues to suggest that vaccination provides improved neutralization of SARS-CoV-2 variants, limited evidence in real-world settings to date corroborates the findings that vaccination can provide improved protection for previously infected persons. The findings from this study suggest that among previously infected persons, full vaccination is associated with reduced likelihood of reinfection, and, conversely, being unvaccinated is associated with higher likelihood of being reinfected.
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These findings suggest that among persons with previous SARS-CoV-2 infection, full vaccination provides additional protection against reinfection. Among previously infected Kentucky residents, those who were not vaccinated were more than twice as likely to be reinfected compared with those with full vaccination. All eligible persons should be offered vaccination, including those with previous SARS-CoV-2 infection, to reduce their risk for future infection.