Updates on Covid19 research:
Title:
Waning of BNT162b2 Vaccine Protection against SARS-CoV-2 Infection in Qatar
"Estimated BNT162b2 effectiveness against any SARS-CoV-2 infection was negligible in the first 2 weeks after the first dose. It increased to 36.8% (95% confidence interval [CI], 33.2 to 40.2) in the third week after the first dose and reached its peak at 77.5% (95% CI, 76.4 to 78.6) in the first month after the second dose. Effectiveness declined gradually thereafter, with the decline accelerating after the fourth month to reach approximately 20% in months 5 through 7 after the second dose. Effectiveness against symptomatic infection was higher than effectiveness against asymptomatic infection but waned similarly. Variant-specific effectiveness waned in the same pattern. Effectiveness against any severe, critical, or fatal case of Covid-19 increased rapidly to 66.1% (95% CI, 56.8 to 73.5) by the third week after the first dose and reached 96% or higher in the first 2 months after the second dose; effectiveness persisted at approximately this level for 6 months."
Source:
https://www.nejm.org/doi/full/10.1056/nejmoa2114114
Title:
Long COVID risk falls only slightly after vaccination, huge study shows
"Vaccination against SARS-CoV-2 lowers the risk of long COVID after infection by only about 15%, according to a study of more than 13 million people. That’s the largest cohort that has yet been used to examine how much vaccines protect against the condition, but it is unlikely to end the uncertainty."
Source:
https://www.nature.com/articles/d41586-022-01453-0
Article:
https://www.nature.com/articles/s41591-022-01840-0
Title:
Duration of mRNA vaccine protection against SARS-CoV-2 Omicron BA.1 and BA.2 subvariants in Qatar
"BNT162b2 effectiveness against symptomatic BA.1 infection was highest at 46.6% (95% confidence interval (CI): 33.4–57.2%) in the first 3 months after the second dose, but then declined to ~10% or below thereafter. Effectiveness rapidly rebounded to 59.9% (95% CI: 51.2–67.0%) in the first month after the booster dose, but then declined to 40.5% (95% CI: 30.8–48.8%) in the second month and thereafter. A similar pattern was observed for mRNA-1273 effectiveness."
Source:
https://www.nature.com/articles/s41467-022-30895-3
Title:
Duration of immune protection of SARS-CoV-2 natural infection against reinfection in Qatar
Pre-print: "Protection of natural infection against reinfection wanes and may diminish within a few years. Viral immune evasion accelerates this waning. Protection against severe reinfection remains very strong, with no evidence for waning, irrespective of variant, for over 14 months after primary infection."
Source (pre-print):
https://www.medrxiv.org/content/10.1101/2022.07.06.22277306v1