Covid-19 likely become seasonal, but not yet, say scientists

Agencies
September 15, 2020

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Beirut, Sept 15: Once herd immunity is attained, the novel coronavirus may follow suit and become a seasonal virus in countries with temperate climates, but until that time, COVID-19 will continue to spread across the seasons, a new study says.

According to the review research, published in the journal Frontiers in Public Health, when a significant section of the population becomes immune to the novel coronavirus and achieves herd immunity, the effective transmission of the virus may drop substantially making it more prone to seasonal fluctuations.

"COVID-19 is here to stay and it will continue to cause outbreaks year-round until herd immunity is achieved," warned study senior author Hassan Zaraket from the American University of Beirut in Lebanon.

"Therefore, the public will need to learn to live with it, and continue practising the best prevention measures, including wearing of masks, physical distancing, hand hygiene, and avoidance of gatherings," Zaraket added.

According to the scientists, there could be multiple waves of COVID-19 before herd immunity is achieved.

Citing earlier research, they said other respiratory viruses similar to the novel coronavirus -- SARS-CoV-2 -- follow seasonal patterns, especially in temperate regions.

They said influenza and several types of coronaviruses that cause common cold are known to peak in winter in temperate regions but circulate year-round in tropical regions.

In the research, the scientists reviewed these seasonal viruses, examining the viral and host factors that control their seasonality as well as the latest knowledge on the stability and transmission of SARS-CoV-2.

They explained that virus survival in the air and on surfaces, people's susceptibility to infections, and human behaviours, such as indoor crowding, differ across the seasons due to changes in temperature and humidity.

These factors influence transmission of respiratory viruses at different times of the year, the study noted.

However, in comparison to other respiratory viruses such as the flu, the scientists said COVID-19 has a higher rate of transmission -- at least partly due to circulation in a largely immunologically naive population.

So unlike the flu and other respiratory viruses, they said the factors governing seasonality of viruses cannot yet halt the spread of COVID-19 in the summer months.

However, once herd immunity is attained through natural infections and vaccinations, they believe the transmission rate of COVID-19 should drop substantially, making the virus more susceptible to seasonal factors.

The researchers said such seasonality has been reported for other coronaviruses, including those that emerged more recently such as NL63 and HKU1, which follow the same circulation pattern like influenza.

"This remains a novel virus and despite the fast-growing body of science about it there are still things that are unknown," Zaraket said.

"Whether our predictions hold true or not remains to be seen in the future. But we think it's highly likely, given what we know so far, COVID-19 will eventually become seasonal, like other coronaviruses," he added.

The scientists noted that the highest global COVID-19 infection rate per capita was recorded in the Gulf states, regardless of the hot summer season.

"Although this is majorly attributed to the rapid virus spread in closed communities, it affirms the need for rigorous control measures to limit virus spread, until herd immunity is achieved," Yassine said.

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Agencies
October 13,2020

New Delhi, Oct 13: The World Health Organization has debunked the idea of herd immunity, saying it is 'scientifically and ethically problematic' and is not an option.

There are some who say the coronavirus be allowed to spread naturally in the lack of a vaccine to achieve immunity in a community.

Herd immunity is achieved by protecting people from a virus not by exposing them to it, said WHO Director General Tedros Ghbreseysus.

"Allowing a dangerous virus that we don't fully understand to run free is unethical. It is not a option," Tedros said in a statement on Monday.

Medical journal Lancet also warned that exposure to the virus does not guarantee future immunity. The second infection may come with more severe symptoms.

The Covid-19 virus has claimed one million lives and still spreading across the world. And there is no vaccine available right now.

Tedros made the comments in the context of China which is preparing to test an entire population of the eastern city Qingdao this week.

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News Network
October 26,2020

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Houston: Indian and Pakistani women are diagnosed with breast cancer, including more aggressive forms, at a younger age, according to a study that provides an insight into understanding the risk factors influencing the disease.

The study, published in the International Journal of Cancer, examined the characteristics of breast cancer among Indian and Pakistani-American and non-Hispanic white women in the US using data from the National Cancer Institute's Surveillance, Epidemiology and End Results Program.

Both, Indian and Pakistani women are diagnosed with more aggressive forms of the disease, at a younger age, according to the researchers.

The researchers, who are part of the Rutgers School of Public Health and Rutgers Cancer Institute of New Jersey, reviewed incidence data among Indian and Pakistani women between 1990 and 2014.

"Our results provide an insight into breast cancer in Indian and Pakistani women, suggesting several hypotheses to guide future scientific studies to better understand the risk factors influencing disease etiology and prognosis," said Jaya M Satagopan, lead author and director of the Center for South Asian Quantitative Health and Education at the Rutgers School of Public Health.

South Asians are the fastest-growing major ethnic group in the United States with breast cancer rates increasing within the population, but little is known about the disease in this socio-culturally unique population, according to the study.

The researchers also reviewed the disease characteristics, treatment and survival data between 2000 and 2016 for 4,900 Indian and Pakistani women and 482,250 non-Hispanic white women with breast cancer.

They found that the occurrence of breast cancer in Indian and Pakistani women was lower than in non-Hispanic white women, however, the number of Indian and Pakistani women diagnosed with breast cancer increased over the years.

Indian and Pakistani women with breast cancer were more likely to be diagnosed at a younger age and at more advanced stages of the disease. In addition, they received more subcutaneous or total mastectomies than non-Hispanic white women, it said.

While the researchers found that Indian and Pakistani women were less likely to die of breast cancer than their non-Hispanic white counterparts, their health was tracked for a shorter time.

Prior cancer research has shown that fewer Indian and Pakistani women participate in scientific studies and that several sociocultural factors may delay their seeking health care.

Research also has shown poor mammogram screening rates in Indian and Pakistani women, which is linked to a lack of family support, lack of transportation, modesty, fear, beliefs that cancer is divine punishment for past deeds, having lived in the United States for less than 10 years, low English proficiency and a lack of faith in the health system.

"Our study indicated that there are important differences in this population that justify further studies to better understand biological, sociocultural, and system level factors such as interactions with the health system, affecting breast cancer screening patterns, diagnosis, risk and survival among South Asian women, given the paucity of literature on this topic,” said the study's senior author Elisa V Bandera, co-leader of the Cancer Prevention and Control Research Program at Rutgers Cancer Institute of New Jersey and professor at Rutgers Robert Wood Johnson Medical School.

The study recommends identifying strategies to better engage Indian and Pakistani women in breast cancer studies and to improve interactions between health care providers and Indian and Pakistani women to identify sociocultural factors associated with screening decisions and health care use in this population.

"As the South Asian population in the United States — and especially in New Jersey — grows, it is imperative that we work to promote health equity in cancer prevention, screening, early diagnosis and treatment through community engagement and a team science approach," said Anita Kinney, director of the Center for Cancer Health Equity at Rutgers School of Public Health and Rutgers Cancer Institute of New Jersey and professor at the Rutgers School of Public Health, who is also one of the study's authors.

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Agencies
October 24,2020

Antibodies against the novel coronavirus follow a classic pattern with a rapid increase within the first three weeks after symptoms, and detectable up to seven months post contracting the disease, according to a new study which assessed 300 patients infected with the virus and 198 post-COVID-19 volunteers.

According to the research, published in the European Journal of Immunology, the participants had antibodies with confirmed neutralisation activity for up to six months post infection with the SARS-CoV-2 virus.

The scientists, led by Marc Veldhoen from Instituto de Medicina Molecular (IMM) in Portugal, monitored the antibody levels of over 300 COVID-19 hospital patients and healthcare workers, 2500 university staff, and 198 post-COVID volunteers.

They setup an in-house sensitive specific and versatile COVID-19 serology test.

The study revealed that 90 per cent of subjects have detectable antibodies up to seven months post contracting COVID-19.

It also found that age was not a confounding factor in levels of antibodies produced, but disease severity is.

"Our immune system recognises the virus SARS-CoV-2 as harmful and produces antibodies in response to it, which helps to fight the virus," Voldhoen said.

"The results of this six months cross-sectional study show a classic pattern with a rapid increase of antibody levels within the first three weeks after COVID-19 symptoms and, as expected, a reduction to intermediate levels thereafter," he added.

Based on the findings, the scientists said men produce more antibodies on average than women, "but levels equilibrate during the resolution phase and are similar between the sexes in the months after SARS-CoV-2 infection".

In the acute phase of the immune response, the researchers observed higher antibody levels in subjects with more severe disease.

They said age is not a confounding factor for the production of antibodies since no significant differences were observed between age groups.

While there was a reduction in the levels of antibodies over time, the team found that there was "robust neutralisation activity" for up to the seventh month post-infection in a large proportion of previously virus-positive screened subjects.

"Our work provides detailed information for the assays used, facilitating further and longitudinal analysis of protective immunity to SARS-CoV-2," Veldhoen said.

"Importantly, it highlights a continued level of circulating neutralising antibodies in most people with confirmed SARS-CoV-2," he added.

The researchers believe the next months will be critical to evaluate the robustness of the immune response to SARS-CoV-2 infection, and to find clues for questions such as the duration of circulating antibodies and the impact of reinfection.

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