chuka_lis

Во Франции в группе из 10 домов престарелых проверили, как обстоит дело с титром антител к шипику коронавируса  у проживающих  (387 резидентов, 75% женщины, медианный возраст 88 лет) и обслуживающего персонала  (257 мед. работников, 81% женщины, 38-54 лет) после прививки.
У всех брали кровь на антитела несколько раз, спустя время, с апреля по июль 2021 года (но не ранее чем через 7 дней после 2 прививки, кто делал 2), чтоб проверить титры и построить модель затухания  гуморального иммунитета.
Серонегативными на коронавирус, согласно прогнозам по модели,  старики, в среднем, становятся через 180 дней, а медики (т к более молодые)- через 220 дней после прививки.  Если человек болел ковидом до прививки, иммунитет, бустированный двойной прививкой, согласно рассчетам, может продержаться около 470 дней.
Если  привившиеся болели ковидом до прививки- то падение уровня антител ниже определяемого порога происходило медленнее.
Так же исследование показало, что  стариков был лучше и дольше иммунный ответ на 2 дозы мРНК вакцины, чем на другие режимы(вакцины). Так что, все же, для самых уязвимых, по мнению авторов, 2 прививки важны, даже если и был ковид ранее.
Для медработников  разница не обнаружилась.
Но у медработников  титры антител после прививок были выше в 2 раза чем у стариков.

In this study, we studied the anti-SARS-CoV-2 IgG(S) level of NH-Res and healthcare workers (HCWs) with or without a history of COVID-19 infection taking into account the time since immunization (COVID-19 and/or vaccination). 654 subjects were analyzed: 397 NH-Res (median age 88, IQR 82-93 years, 75% women) and 257 Health Care Workers (HCWs, median 46, IQR 38-54 years, 81% women). NH-Res and HCWs were classified in one of the following 3 groups: No-COVID history and 2 vaccine shots (COV-NO/2VACC); Yes-COVID history and 1 (COV-YES/1VACC) or 2 (COV-YES/2VACC) vaccine injections. The time-related decrease in IgG (S) in subjects without COVID-19 history, SARS-COV-2 serology would be negative in HCWs approximately 220 days and in residents 180 days after vaccination. This time-related decrease was much slower in those with history of COVID. NH-Res belonging into the COV-NO/2VACC and the COV-YES/1VACC groups showed lower IgG (S) levels than the same groups of HCWs (for both groups, p<0.0001), whereas in the group COV-YES/2VACC, IgG (S) levels were similar in NH-Res and HCWs (p=0.88). These results remained unchanged after adjustment for age and duration since immunization. Thus, in NH-Res, 2 vaccine shots were associated with a more pronounced immune response, whereas in HCWs, 1 or 2 vaccine shots in patients with COVID-19 history did make any difference. These results indicate significant differences in mRNA vaccination between NH-Res and middle-aged controls, and could contribute to the specification of vaccine policy in this very old, frail population.
In the present study,we evaluatedthe SARS-CoV-2 IgG(S) antibody response to the vaccination in NHs residents i.e. in a very old (88 years at mean), frail population which is one of the most vulnerable population for having severe forms of COVID-19. Although IgG(S)levels represent just a part of the global immunity response(8), it has been shown that “compromised immune responses to the SARS-CoV-2 spike isa major trait of COVID-19 patients with critical conditions“(9). In the present study, the results obtained in the different NH-Res groups were compared with those of middle-aged HCWswith or without a history of COVID-19 infection.Thiscomparison showed lower levels of IgG(S) in the NH-Res population in two groups: COVID-NO/VACC2 and COVID-YES/VACC1. In contrast, in the COVID-NO/VACC2,NH-Res and HCWs showed similar IgG (S) levels,indicating that the second injectionof mRNA vaccine, 3 to 6 weeks after the first shot, significantly increased IgG (S) valuesin the very old frail subjects.One could ask that inall these groups median IgG (S) values were clearly higher than the threshold of positivity (10-13 AU/ml)and therefore differences among the different groups are clinically not relevant. However,a recent study has shown that only sera with mean IgG(S)level >126 AU/mLwere associated with a neutralizing activity of SARS-CoV-2 on Vero E6 cells (Neutralizing titer 50 ≥40) (10).Therefore, it is reasonable to look for high IgG(S) levels especially in the very old, vulnerable patients.In the present study,NHresidents develop the highest antibody levels only if they have both history of COVID and 2 injections of the vaccine i.e.threeSARS-CoV-2 immune stimulations,whereas in younger subjects 2 immune stimulations (COVID-NO/VACC2 or COVID-YES/VACC1)is necessaryto obtain high IgG(S)levelsas it has previously reported (4,5).However, even in HCWS, COVID-YES/VACC1 was associated with higher IgG(S) as compared with the COVID-NO/VACC2. Indeed, in both populations (NH-Res and HCWs),previoushistory of COVID-19 was associated with higher IgG (S) response to the vaccine. This is more pronounced in old age NH-Res,in which median values are particularly lower in the (COVID-NO/VACC2) as compared with all other vaccinated groups. For subjects with history of COVID-19, a longer time delay is estimated: about 470 days, from vaccination in HCWs and for NH-Res we did not observe a significant decrease in the IgG level during the follow-up after 2 post-COVID vaccine shots.