Readers are demanding citations proving natural immunity is far better than vaccine-induced immunity for Covid. As my readers know I scan large amouns of material and cannot recall all the epi stats on this subject, but below are 4 references I just found, 2 on waning vaccine immunity, one on the rarity of repeat covid infections in healthcare workers, one on repeat infections in Indians.
The other type of evidence is the persistence of T cell immunity after vaccination. A convincing report on this came out in the past 2 weeks by the La Jolla team of immunologists that includes Shane Crotty.
About half of adults infected in an outbreak of the Delta variant of Covid-19 in Israel were fully inoculated with the Pfizer vaccine, according to a clarification by Prof. Balicer of an earlier statement. An earlier version of this article incorrectly said about half of people infected in the outbreak were fully inoculated.
“As seen in real world data released from the Israel Ministry of Health, vaccine efficacy in preventing both infection and symptomatic disease has declined six months post-vaccination, although efficacy in preventing serious illnesses remains high,” the statement said, according to multiple news outlets.
Israeli officials are reporting a 30% decrease in the effectiveness of the Pfizer COVID-19 vaccine to prevent infection and mild to moderate cases. At the same time, however, protection against hospitalization and severe illness remains robust.
The country’s Ministry of Health data shows high levels of circulating Delta variant and a relaxation of public health measures in early June led to a drop in the vaccine’s prevention of “breakthrough” cases from 94% to 64% in recent weeks.
The data suggest that repeat infections are rare — they occurred in fewer than 1% of about 6,600 participants who had already been ill with COVID-19.
New Delhi: Reinfection among people who have recovered from COVID-19 is rare and natural immunity after illness lasts around nine months, a study involving long term follows up of more than 1,000 people in Pune has found.
According to the Times of India, a study conducted by epidemiologists and community medicine experts from the DY Patil Medical College and Hospital in the city tracked 1,081 people who showed SARS-CoV-2 antibodies during a serosurvey in September last year until this past June. During the nine months of observation, just 13 participants – just 1.2% – were reinfected. The study, which is still in pre-print, also found that all those who were reinfected only had mild cases of COVID-19 and made a full recovery.