In December 2019, a cluster of patients with pneumonia of unknown cause was linked to a
seafood wholesale market in Wuhan, China. A previously unknown betacoronavirus was …

However, this information was from what now appears to be first-generation cases from a point
source, but at the time it seems that a second generation, and perhaps a third generation, …

Background The initial cases of novel coronavirus (2019-nCoV)–infected pneumonia (NCIP)
occurred in Wuhan, Hubei Province, China, in December 2019 and January 2020. We …

Human coronaviruses (HCoVs) were first described in the 1960s for patients with the common
cold. Since then, more HCoVs have been discovered, including those that cause severe …

Background In late December, 2019, patients presenting with viral pneumonia due to an
unidentified microbial agent were reported in Wuhan, China. A novel coronavirus was …

Background Infection of poultry with influenza A subtype H7 viruses occurs worldwide, but the
introduction of this subtype to humans in Asia has not been observed previously. In March …

Vaccines are urgently needed to control the coronavirus disease 2019 (COVID-19) pandemic
and to help the return to pre-pandemic normalcy. A great many vaccine candidates are …

Background China has undergone rapid demographic and epidemiological changes in the
past few decades, including striking declines in fertility and child mortality and increases in …

Background Although several COVID-19 vaccines have been developed so far, they will not
be sufficient to meet the global demand. Development of a wider range of vaccines, with …

Background Human infections with different avian influenza viruses—eg, H5N1, H9N2, and
H7N9—have raised concerns about pandemic potential worldwide. We report the first …