chuka_lis (chuka_lis) wrote,
chuka_lis
chuka_lis

Почему не только прививки важны

Для того, чтобы бороться в эпидемией (и пандемией).
Если вирус сравнительно свободно циркулирует, особенно среди тех, кто может быть ослаблен- высока вероятность появления более вирулентного штамма. Который может и обойти защиту, вызыванную вакцинацией или предыдущей болезнью.
Например, в Бразилии, как отмечаают исследователи, во вторую волну разошелся вариант коронавируса Р.1, или гамма, который вызвал повышенную заболеваемость среди более молодых (20-59 лет), причем с высокой госпитализацией (каждый третий) и нуждаемостью в интенсивной терапии, да и смертность у него оказалась повыше, особенно среди молодых же (хотя у них в стране итак смертность от ковида высокая).
Так уж получается, что иммунитет, который обеспечивает прививка от ковида, не является долговременным и может не препятствовать заражению и передаче вируса.
Потому другие меры, предовтращающие распространеие вируса, по-прежнему актуальны.

In late 2020 and early 2021, new waves of the COVID-19 outbreak have caused an unprecedented sanitary collapse in Brazil. Unlike the first COVID-19 wave, in subsequent waves, preliminary evidence has pointed to an increase in the daily reported cases among younger people being hospitalized, overloading the healthcare system. In this comprehensive retrospective study, confirmed cases of hospitalization, ICU admission, IMV requirement and in-hospital death from Brazilian COVID-19 patients throughout 2020 until the beginning of 2021 were analyzed through a spatio-temporal study for patients aged 20-59 years...
Unlike othercountries, we had already seen a high proportion of hospitalization (47.07%) and lethality (23.0%) among young adults (20-59years) during the first wave. In order to estimate in-hospital deaths among hospitalized young adults, we used case fatality rate. The hCFR varied significantlyamong the analyzed periods (Figure6, TableS4). The highest hCFR in T2 is given in São Paulo, Rio de Janeiro, Ceará andPernambuco states, while at T6 accounts for São Paulo, Minas Gerais and Rio Grande do Sul, accompanying the increase in thenumber of hospitalization cases in these states in such periods, respectively. Amazonas state shows a significant proportion ofdeaths during T1 and T5.1 There was a substantial increase in mortality in absolute numbers as well as in the percentages, mainly in T5 (13,892deaths; 19.0%) and T6 (42,999 deaths; 28.6%) compared to T4 (6,519 deaths; 14.8%.
A preliminary study carried out with patients from the Paraná state has indicated a significant increase in case fatality rates in young and middle-agedadults in February 2021, corresponding to the spreading period of P.1 variant in the country26. These findings show that thevariant P.1 spread rapidly across Brazilian territory and may be one of the factors responsible for the high hospitalization andmortality of younger people.
The analysis showed that Brazil is experiencing a numerical explosion of hospitalizations and deaths for patients aged 20-59 years, especially in the state of Sao Paulo, with a similar proportion of hospitalizations for this age group but higher proportion of deaths compared to the first wave.

The Delta variant attenuated vaccine-associated reductions in transmission: two BNT162b2 doses reduced Delta transmission , more than ChAdOx1. Variation in viral load (Ct values) explained only a modest proportion of vaccine-associated transmission reductions. Transmission reductions declined over time since second vaccination, for Delta reaching similar levels to unvaccinated individuals by 12 weeks for ChAdOx1 and attenuating substantially for BNT162b2. Protection from vaccination in contacts also declined in the 3 months after second vaccination. Conclusions Vaccination reduces transmission of Delta, but by less than the Alpha variant. The impact of vaccination decreased over time. Factors other than PCR-measured viral load are important in vaccine-associated transmission reductions. Booster vaccinations may help control transmission together with preventing infections.

We found no significant difference in cycle threshold values between vaccinated and unvaccinated, asymptomatic and symptomatic groups infected with SARS-CoV-2 Delta. Given the substantial proportion of asymptomatic vaccine breakthrough cases with high viral levels, interventions, including masking and testing, should be considered for all in settings with elevated COVID-19 transmission.

 
Tags: коронавирус, статьи, эпидемия
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