SarS-CoV-2 (green) particles hide in the intestinal cells of a study participant 92 days after the onset of symptoms. Source: C. Gaebler et al./Nature By modelling the spread of P.1 and its potential effects during the second wave of Manaus, the researchers estimated that the variant was 1.4-2.2 times more transmissible than other lineages and that it was able to bypass some of the immunity conferred by previous infections. The results have not yet been reviewed. Moritz Kraemer of the University of Oxford, UK, and colleagues modelled the spread of SARS-CoV-2 by communities of different sizes and population densities (B. Rader et al. Nature Med. doi.org/fcjk; 2020). The researchers validated their model by comparing its findings with known data on individual movements and infection rates in overcrowded Chinese cities such as Wuhan and Italy`s less densely populated provinces.
Nearly 250 of the groundbreaking infections occurred in people who had received only one of the two recommended vaccine doses. The researchers compared these infections with the same number of infections in unvaccinated people that matched age, date of infection and other characteristics. The comparison revealed that infections in partially immunized individuals were slightly more likely to be caused by B.1.1.7 than in unvaccinated individuals. Weifeng Shi of Shandong First Medical University and Shandong Academy of Medical Sciences in Taian, China, and colleagues examined 302 fecal and urine samples and 109 oral swabs from 342 live bats between May 2019 and November 2020 (H. Zhou et al. Preprint at bioRxiv doi.org/gh73mk; 2021). The researchers captured and released all the bats that represented nearly two dozen species on an area of about 1,100 acres, less than a tenth the size of San Francisco, California. Of all included articles and studies, 192 (77.1%) were published in peer-reviewed journals, 35 (14.1%) were published on preprint servers, and 22 (8.8%) were published on the official websites of public health agencies. The journal with the highest number of articles was The Lancet with 13 (6.8%) articles published.
Of the preprinted articles, most (n = 28) were published on BioRxiv. The articles published on the Official websites were mainly COVID-19 guidelines, including 10 preliminary WHO guides, nine US CDC preliminary guidelines/guidelines, two ECDC guidelines and one directive from the Communicable Diseases Network Australia (CNDA). Find free access to the latest RESEARCH and articles on COVID-19 Andrew Clark of the London School of Hygiene & Tropical Medicine and colleagues have studied the prevalence of diabetes, cardiovascular problems and other conditions that predispose people infected with SARS-CoV-2 to severe COVID-19 (A. Clark et al. Lancet Glob. doi.org/dzk9; 2020). Analyzing data from 188 countries, the team estimates that 1.7 billion people worldwide have an increased risk of “serious” disease. The researchers also estimate that nearly 350 million people – some of whom have no underlying conditions – would need hospitalization if infected. Other mutations could contribute to the behavior of B.1.1.7, the researchers say, but the disproportionate effects of N501Y on transmission make it particularly careful in other variants. The results have not yet been reviewed. The researchers found that adults living with children – especially high school students – who went to school were more likely to report symptoms of covid-19 or test positive for SARS-CoV-2.
But the researchers also found that schools could completely eliminate this risk by implementing at least seven mitigation measures from a list that included wearing masks for students and teachers, preventing parents from entering schools and increasing the distance between offices. The results have not yet been reviewed. A team led by Chuan Qin of Peking Union Medical College in Beijing injected rhesus monkeys (Macaca mulatta) with three doses of a vaccine composed of chemically inactivated SARS-CoV-2 particles (Q. Gao et al. Preprint at bioRxiv doi.org/dskt; 2020; not reviewed before publication). Eight monkeys were then deliberately exposed to the virus. About a month later, the research gave the monkeys another dose of the virus. Over the next two weeks, the team discovered low and rapidly decreasing levels of viral RNA in the animals` noses and almost none in the monkeys` lungs. All the monkeys responded to antibodies to the second dose of SARS-CoV-2, suggesting that their immune systems had fought the virus.
Kate Bubar and Daniel Larremore of the University of Colorado at Boulder and their colleagues modeled the effects of introducing a vaccine when different age groups are prioritized (K.M. Bubar et al. Preprint at medRxiv doi.org/ghj6xw; 2020). The researchers also looked at the impact of the rate of spread of the virus in the population, the speed of delivery of the vaccine and the effectiveness of the protection provided by the vaccine. Scientists detected coronavirus RNA in coarse droplets and finer “aerosol droplets” emitted by volunteers who were not wearing masks. The mask reduced the detection of viral RNA in both types of droplets. Larger particles are carried by sneezing and coughing, while exhaled breath can spread aerosol droplets five microns or less in diameter. Neutralizing antibodies to SARS-CoV-2 block particles of the virus, making it one of the body`s most powerful weapons against the new pathogen. Most of the neutralizing antibodies studied by the researchers target a region of the virus` spike protein called the receptor binding domain (RBD). However, previous studies have also identified neutralizing antibodies that act against other parts of the tip, particularly a region called the N-terminal domain (NTD).
The researchers conclude that most Wuhan residents are still susceptible to SARS-CoV-2 infection and that a mass vaccination campaign is needed to achieve herd immunity. WHO is bringing together scientists and professionals from the global health professions to accelerate the research and development process and develop new standards to contain the spread of the coronavirus pandemic and support care for those affected. The researchers say early isolation of cases prevented transmission that would otherwise have occurred later in an infectious period, resulting in fewer cases and slowing the spread of the virus. As a result, most of the remaining transmissions occurred either before infected people showed symptoms or at the beginning of the symptomatic phase, and the serial interval decreased. The team found that about 43% of people infected with SARS-CoV-2 in the city did not report fever or other symptoms (E. Lavezzo et al. Preprint at medRxiv doi.org/ggsmcj; 2020; not peer-reviewed before publication). The researchers observed no statistically significant difference in potential infectivity between those who reported symptoms and those who did not. The researchers found that out of three people who died within a month of testing positive for a previously circulating viral variant, about five died after testing positive for B.1.1.7. .