Global trends in COVID-19

Abstract

The pandemic COVID-19 is certainly one of the most severe infectious diseases in human history. In the last 2 years, the COVID-19 pandemic has caused over 418.6 million confirmed cases and 5.8 million deaths worldwide. Young people make up the majority of all infected COVID-19 cases, but the mortality rate is relatively lower compared to older age groups. Currently, about 55.04% individuals have been fully vaccinated rapidly approaching to herd immunity globally. The challenge is that new SARS-CoV-2 variants with potential to evade immunity from natural infection or vaccine continue to emerge. Breakthrough infections have occurred in both SARS-CoV-2 naturally infected and vaccinated individuals, but breakthrough infections tended to exhibit mild or asymptomatic symptoms and lower mortality rates. Therefore, immunity from natural infection or vaccination can reduce SARS-CoV-2 pathogenicity, but neither can completely prevent SARS-CoV-2 infection/reinfection. Fortunately, the morbidity and mortality of COVID-19 continue to decline. The 7-day average cumulative case fatality of COVID-19 has decreased from 12.3% on the February 25, 2020, to 0.27% on January 09, 2022, which could be related to a decreased SARS-CoV-2 variant virulence, vaccine immunization, and/or better treatment of patients. In conclusion, elimination of SARS-CoV-2 in the world could be impossible or at least an arduous task with a long way to go. The best strategy to prevent COVID-19 pandemic is to expand inoculation rate of effective vaccines. As the population reaches herd immunity, the mortality rate of COVID-19 may continue to decrease, and COVID-19 could eventually become another common cold.

Keywords: Breakthrough infection; COVID-19; Case fatality rate; Delta variant; Herd immunity; Omicron variant; SARS-CoV-2; Vaccine.

Fig. 1

Top 25 Countries with cumulative cases per 100,000 population as of February 18, 2022 (https://covid19.who.int/). (Color version of figure is available online).

Fig. 2

Top 25 Countries with cumulative cases per 100,000 population from February 12, 2022 to February 18, 2022 (https://covid19.who.int/). (Color version of figure is available online).

Fig. 3

Top 25 Countries with cumulative deaths per 100,000 population as of February 18, 2022 (https://covid19.who.int/). (Color version of figure is available online).

Fig. 4

Distribution of COVID-19 cases, deaths, and CFR in different age groups in the United States as of February 18, 2022 (https://covid.cdc.gov/covid-data-tracker/#datatracker-home). (Color version of figure is available online).

Fig. 5

Worldwide 7-day average CFR of COVID-19 from January 22, 2020, to January 9, 2022 (https://www.worldometers.info/coronavirus/). (Color version of figure is available online).

Fig. 6

Worldwide 7-day average COVID-19 cases and deaths as of January 9, 2022 (https://www.worldometers.info/coronavirus/). (Color version of figure is available online).