Global Science News | Pandemics similar to COVID-19 may occur every year

Public Health A pandemic similar to COVID-19 is likely to occur every year with a 2% probability

The COVID-19 pandemic may be the deadliest global epidemic in more than a century. But a new study published in the Proceedings of the National Academy of Sciences suggests that similar extreme events may not be rare. The study used new statistical methods to measure the scale and frequency of outbreaks of various infectious diseases over the past 400 years (since 1600) without timely medical intervention, covering a range of infectious diseases including plague, smallpox, cholera and new influenza epidemics.

The study points out that in any year, the probability of a pandemic with a similar impact to COVID-19 is about 2%, and this probability is still growing. The researchers found that in addition to COVID-19, the probability of an epidemic of similar scale to the 1918 influenza pandemic (so far, the pandemic with the highest death toll, killing more than 25 million people) is 0.3% to 1.9% per year. In the next few decades, the probability of an outbreak of a new infectious disease may increase threefold; in the next 1,200 years, a pandemic that endangers all of humanity may occur. The researchers pointed out that population growth, environmental degradation, and more contact between humans and disease-carrying animals may be important reasons for the increased probability of infectious disease outbreaks, and humans need to increase the priority of emergency response and control and prevention of infectious diseases.

· Astronomy ·

Asteroid with the shortest orbital period discovered

Image credit: KATHERINE CAIN AND SCOTT SHEPPARD, COURTESY OF THE CARNEGIE INSTITUTION FOR SCIENCE

Asteroids within the Earth's orbit are difficult to detect. Because from the Earth's perspective, their positions in the sky are relatively close to the Sun, and observations are easily disturbed by the Sun. Astronomers can only search for them around sunrise and sunset. On the evening of August 13, astronomers used the Victor M. Blanco Telescope equipped with the Dark Energy Camera to discover the asteroid 2021 PH27 with the shortest known orbital period. After supplementing the observation data with other telescopes, the asteroid parameters were made public in a report.

The asteroid 2021 PH27 has an orbital period of 113 days, an orbital semi-major axis of 70 million kilometers, a perihelion within the orbit of Mercury, and aphelion outside the orbit of Venus. The diameter of the asteroid is about 1 kilometer. When the asteroid reaches perihelion, its surface temperature can reach 500 degrees Celsius. Its orbital inclination is 32 degrees, indicating that it may originate from the outer solar system. Since its orbital perihelion is the closest to the sun among the known celestial bodies in the solar system, the general relativistic effect of the sun's gravitational field on it is also the most obvious, and its orbit may precess by 1 arc minute per century.

Genetics

Why homosexual behavior has not disappeared in evolution

Previous studies have confirmed that although same-sex sexual behavior disperses mating opportunities and reduces survival advantages, it is heritable, which means it has evolutionary continuity. Recently, in a study published in Nature Human Behavior, researchers conducted a genome-wide association study (GWAS) on more than 470,000 people from the UK and the US who had same-sex sexual behavior and nearly 360,000 people who had only heterosexual sexual behavior, analyzing the genetic effects of same-sex sexual behavior. In addition, they also counted the number of partners that the subjects who had only heterosexual sexual behavior had.

The researchers found that when there are genetic effects associated with same-sex sexual behavior in people who have only had opposite-sex partners, they may have more opposite-sex partners. The researchers pointed out that having more partners is a sign of successful courtship, which will lead to more offspring in evolution. And this genetic effect may help explain why same-sex sexual behavior has persisted throughout the evolution of the human species: this may be because this behavior can bring more offspring and is favored in the evolutionary process. The authors also pointed out that this study has many limitations and should be interpreted with caution. For example, the data used in this study only came from individuals with European ancestors in the United Kingdom and the United States, and therefore can only represent a small part of human genetic and behavioral diversity.

· COVID-19 vaccine ·

The overall protection rate of the domestically produced COVID-19 vaccine against the Delta strain is 59%

Image source: Pixabay

Previous studies have shown that the protective efficacy of the COVID-19 vaccine against the Delta strain of the new coronavirus has decreased, but the protective efficacy of the Chinese COVID-19 inactivated vaccine against it is still unknown. To this end, the Guangzhou Center for Disease Control and Prevention, together with the Zhong Nanshan team and the Zhang Dingmei team of the School of Public Health of Sun Yat-sen University, conducted a real-world study to estimate the protective effect of the domestic COVID-19 inactivated vaccine against the Delta strain. The study has been published in Emerging Microorganisms and Infections.

The researchers collected data on cases and close contacts aged 18 to 59 in the COVID-19 outbreak in Guangzhou caused by the Delta strain from May to June this year. The analysis results showed that after completing two doses of vaccination, the overall protection rate of the two domestically produced inactivated COVID-19 vaccines was 59.0%, which has reached the 50% protection rate standard set by the World Health Organization; the protection rates for preventing moderate COVID-19 and severe cases were 70.2% and 100%, respectively. At the same time, with only one dose of vaccination, the protection rate of the vaccine was only 13.8%. In addition, after completing two doses of vaccination, the vaccine had a higher protection rate for people aged 40 to 59 and women. The study showed that after completing two doses of vaccination, the domestically produced inactivated COVID-19 vaccine was generally effective against the Delta strain, but only one dose of the vaccine could not produce sufficient protection.

· COVID-19 vaccine ·

US FDA grants full use authorization for Pfizer's COVID-19 vaccine

The U.S. Food and Drug Administration (FDA) approved the full use authorization of the Pfizer-BioNTech COVID-19 vaccine on Monday, making it the first COVID-19 vaccine to receive full authorization for use in the U.S. The current full approval is limited to those aged 16 and above, and the age group of 12 to 16 is still in the emergency approval stage.

After FDA review, the Pfizer-BioNTech vaccine causes almost no serious adverse reactions; six months after vaccination, its effectiveness against severe COVID-19 infection can still be maintained at 97%. The FDA's approval of the Pfizer-BioNTech COVID-19 vaccine means that it meets the highest standards for US vaccines. After the FDA took action, the New York government, the Pentagon, and universities all responded quickly and will force employees and students to be vaccinated. In addition, the FDA has recently authorized the third dose of the Pfizer-BioNTech vaccine for people with compromised immune systems. However, more research data is needed to expand the population for the third dose of the vaccine.

COVID-19

In 2020, the economic recession caused by the pandemic may cause 267,000 additional infant deaths in low- and middle-income countries

The global economy contracted by nearly 5% in the first year of the COVID-19 pandemic, adding 120 million people to the poor. The economic shock of the pandemic could increase the death toll among vulnerable groups such as young children and the elderly in low-income countries. In a study recently published in the British Medical Journal, researchers used modeling to estimate the impact of the economic recession caused by the 2020 COVID-19 pandemic on the survival of infants aged 0 to 1 year in 128 low- and middle-income countries. Their calculations showed that infant deaths in low- and middle-income countries increased by 267,208 in 2020, a 7% increase over the expected number of infant deaths that year. The region with the highest number of additional infant deaths was in South Asia, with an additional 113,141 infant deaths. The researchers analyzed several reasons for the increase in infant deaths: poverty at the household level could lead to poorer nutrition and care for infants, while economic recessions could also affect the supply and quality of health system services.

COVID-19

As of 10:00 Beijing time on August 24, according to the latest statistics from Johns Hopkins University, the global cumulative number of confirmed cases of COVID-19 was 212,480,805, with 4,440,279 deaths.

According to the official website of the National Health Commission, from 0:00 to 24:00 on August 23, 31 provinces (autonomous regions, municipalities) and the Xinjiang Production and Construction Corps reported 35 new confirmed cases, including 34 imported cases (9 in Shanghai, 8 in Guangdong, 7 in Zhejiang, 4 in Yunnan, 2 in Fujian, 2 in Sichuan, 1 in Tianjin, and 1 in Shaanxi), and 1 local case (in Henan); no new deaths; 1 new suspected case, an imported case (in Shanghai).

31 provinces (autonomous regions, municipalities) and the Xinjiang Production and Construction Corps reported 9 new asymptomatic infections (all imported from abroad); 5 cases were converted to confirmed cases on the same day (all imported from abroad); 20 cases were released from medical observation on the same day (19 cases were imported from abroad); 491 asymptomatic infections are still under medical observation (405 cases were imported from abroad).

Text: Zhang Chu, Li Shiyuan, Wang Yibo, Bai Defan Editor: Shi Yunlei, Wang Yu Cover source: Pixabay

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