A Preprints with The Lancet research paper entitled "Women May Play a More Important Role in the Transmission of the Corona Virus Disease (COVID-19) than Men" was published on the Preprints server and early research platform SSRN on March 3, 2012. Transmission of the Corona Virus Disease (COVID-19) than Men", the team from the People's Hospital of Wuhan University analyzed for the first time the possible specificity of women in the transmission of the novel coronavirus.
The author team is from various departments of Wuhan University People's Hospital, including the Department of Oncology, the Department of Geriatrics, and the Department of Critical Care Intensive Care Medicine. Corresponding authors are Dong Weiguo, chief physician of the Department of Gastroenterology at the hospital, and Xu Yu, chief physician of the Department of Otolaryngology at the hospital.
This study shows for the first time that women exhibit different characteristics from men in the transmission of COVID-19. Women not only have relatively mild symptoms but also have a longer incubation period than men, which may be due to the fact that women are born with stronger antiviral immunity than men.
Accordingly, the team calls for women to be tested for nucleic acid during screening, regardless of whether they are symptomatic, as long as their exposure history is clear, and for women under medical observation to be isolated for periods longer than 14 days.
To date, COVID-19 has been identified as a highly infectious virus with outbreaks in multiple countries and regions around the world, the team said. Various studies have reported on its epidemiology, clinical features, prognosis and treatment experience, but no specific epidemiological studies on women in the transmission of the disease are available. The researchers suggest that female characteristics may be a key point in influencing the spread of COVID-19.
The researchers used the keywords "novel coronavirus," "2019-nCoV," "COVID-19" and "novel Coronavirus pneumonia" in the databases PubMed, Web of Science and China Knowledge Network (CNKI) to search for relevant articles published up to February 14, 2020.
Ultimately, the team reviewed nine articles that included analysis of confirmed cases. From them, the researchers extracted information on the source of case information, when the cases were collected, average age, number of cases, and gender ratio.
In addition, the team retrospectively analyzed all patients diagnosed with COVID-19 at Wuhan University People's Hospital before February 20, 2020, dividing them into mild, moderate, severe (severe), and critical (critical) groups and comparing the sex ratio and mean age of each group. The team also compared differences in the sex ratio of diagnosed cases across time.
The team found that the majority of confirmed cases were concentrated in men and were more pronounced in patients admitted to the ICU. Of the 6,013 patients for whom the team collected data, most were admitted or confirmed between Jan. 1 and Jan. 29 of this year, with 3,361 (55.9 percent) of them being male. Of these, a total of 975 were admitted to the ICU, of which 573 (58.8%) were male.
These results may represent that men are more likely to be infected with COVID-19 than women, and have more severe symptoms after infection.
However, it is worth noting that the team also found that the proportion of confirmed cases among males in Wuhan gradually decreased during three periods, namely before January 1, from January 1 to January 11, and from January 12 to January 22, at 66.0%, 59.3%, and 47.7%, respectively.
Meanwhile, 34.0% of patients diagnosed during the initial phase of the outbreak, i.e., before January 1, were female, while the proportion of females gradually increased to 45.0% by January 26 in the subsequent study.
The team's review of the literature yielded a relationship between patient admission time and sex ratio, among others
One hint given by this feature is that the proportion of newly diagnosed males declined as the duration of the outbreak increased.
The team further analyzed the 2045 cases (953 males and 1092 females) diagnosed at the hospital as of February 20 of this year. There were 454 cases (47.6% of all males) and 612 cases (56.0% of all females) in the mild to moderate group; 387 cases (40.6%) in the severe group for males and 404 cases (37.0%) for females; and 112 cases (11.8%) in the critical group for males and 76 cases (7.0%) for females.
Relationship between patient gender and disease severity in hospital data statistics
In addition, the researchers identified 67 asymptomatic infections in the data, 47 of which were in females. This suggests that females not only make up a large percentage of mild to moderate patients, but also a large percentage of asymptomatic infections.
The data suggest that more male patients were admitted to the hospital than female before January 20, but more female patients than male patients after that date. Both the literature and the data from this hospital suggest that females accounted for a lower proportion of admissions early in the outbreak, but that this proportion increased later in the outbreak.
Proportion of male and female patients at different time periods
These data may suggest that women are not only relatively less symptomatic but may also have a longer incubation period than men, perhaps because women are naturally more immune to the virus than men. Just because a woman is not diagnosed in the first stage does not mean that she is not infected, only that her symptoms are milder or asymptomatic.
The prevailing explanation is that the interaction between sex hormones and the immune system makes men more susceptible to pathogens than women.
In general, women tend to develop a stronger immune response, which helps them clear infections faster and reduces the risk of ongoing disease progression. But as long as a viral infection exists, the virus will keep fighting the body's immune system. The body has no symptoms of the disease until the virus breaks through the immune system, which is the incubation period.
"When your immunity is able to fight off the virus longer, but not kill it completely, you have a longer incubation period." The authors write.
The asymptomatic onset and long incubation period in women will undoubtedly have an important impact on the spread of the new coronavirus. For example, infected women who come into contact with others because they are asymptomatic, even after active or passive isolation has ended, may still "escape" diagnosis and cause subsequent transmission of the virus. A specific case with a long incubation period and high transmission rate was also recently reported in a woman.
In summary, the authors concluded that the number of men and women who eventually become infected with COVID-19 should be similar. Over time, more female patients with long incubation periods are diagnosed and so the proportion of female patients gradually increases. However, it is worth noting that studies have shown that infected men are much sicker than women, and these phenomena may be attributed to women's naturally stronger immunity against the virus.
Based on the results of this study, the team calls for China and other countries or regions of the world to adopt differentiated disease control measures for women as soon as possible. For example, nucleic acid testing should be performed directly on women with a clear history of exposure during screening, regardless of whether they are symptomatic, and women under medical observation should also be isolated for more than 14 days.
The team also called on the CDC and other health authorities in China to "further study the role of women in the epidemic and develop separate isolation and diagnostic programs for women as soon as possible (We call on China and the rest of the world to adopt differential control measures for women as soon as possible). control measures for women as soon as possible" and stated, "Perhaps this will speed up the end of the epidemic and reduce the cost of its control. epidemic and reduce the cost of controlling it."
