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Infectious Diseases

05 October 2020

Coronavirus research recap: How the common cold could offer protection, and severe Covid in men

How the common cold could potentially protect you against Covid-19; and more evidence shows why Covid mortality rate is higher in men

LATEST SCIENCE AND RESEARCH

READ | How the common cold could potentially protect you against Covid-19

Common colds can make us feel lousy, but according to a new study from infectious disease experts at the University of Rochester Medical Centre, the colds we’ve had in the past could potentially play a role in protecting us against Covid-19.

The study was published in mBio and is the first to show that SARS-CoV-2, the virus that causes Covid-19, induces memory B cells – immune cells that last for a long time and detect and destroy pathogens.

These clever cells also remember some pathogens, so that they can destroy them next time, before infection even starts. Memory B cells are said to last for decades and researchers are still investigating whether those who have had Covid-19 will be protected by these cells.

The study reported that memory B cells can cross-react, which means that those cells that attacked your common cold might be clever enough to recognise SARS-CoV-2.

As some common colds are also caused by coronaviruses, there is the possibility that there could be pre-existing immunity against SARS-CoV-2 in some people. And according to the researchers, this is nearly all of us.

"When we looked at blood samples from people who were recovering from Covid-19, it looked like many of them had a pre-existing pool of memory B cells that could recognise SARS-CoV-2 and rapidly produce antibodies that could attack it," said lead study author Mark Sangster, PhD, research professor of Microbiology and Immunology at URMC in a news release.

READ | More evidence shows why Covid mortality rate is higher in men

Scientists have been trying to understand why Covid-19, the disease caused by SARS-CoV-2, affects men more severely than women.

Previous studies have found clues in the presence of antibodies, as well as the immune responses in the two sexes. And two recent studies offer further explanations.

Both published papers were presented at the ESCMID Conference on Coronavirus Disease (ECCVID), which took place online from 23–25 September, EurekAlert reports.

One is a German study that confirms that men have a higher risk of Covid-19 associated death compared with women, and researchers found that this is possibly related to higher levels of inflammation in men.

The second study by researchers from the Netherlands explains that Covid-19 mortality in men could be explained by differences in circulating proteins and immune system cells.

The German study, led by Dr Frank Hanses from University Hospital Regensburg in Germany, and colleagues, showed that men have a 62% increased risk of Covid-19 associated death compared with women. This was after adjusting for various factors.

READ | Study sheds light on why Covid-19 hits elderly hardest

Elderly people who get Covid-19 have lower levels of important immune cells, which may explain why they are more likely than younger patients to have severe symptoms or die, new research suggests.

For the study, the researchers analysed blood samples from 30 people with mild Covid-19, ranging in age from the mid-20s to late-90s. Compared with healthy people, all of the Covid-19 patients had lower numbers of T cells – which target virus-infected cells – in their blood.

But Covid-19 patients over 80 years of age had fewer T cells than those who were younger, and so-called "killer" T cells in older patients produced lower amounts of cytotoxic molecules that find and kill infected cells, the investigators found.

This age-related difference in immune response may partially explain why older Covid-19 patients have more severe illness, according to the authors of the study published online on 21 September in the journal mBio.

"Elderly people have more severe diseases compared to young people, and we found that the cytotoxic part of immune control is not as efficient to respond to the virus in older people," said study leader Gennadiy Zelinskyy, a virologist at University Hospital Essen, in Germany.

The lower levels of T cells in Covid-19 patients is among the many unwelcome surprises of the pandemic, he noted in a news release from the American Society for Microbiology.

READ | Certain cancer treatments may heighten danger from Covid-19

People with cancer are at increased risk for severe Covid-19. Now, a preliminary study suggests that certain cancer therapies may heighten those odds even further.

Researchers found that of 3 600 US cancer patients who contracted Covid-19, the highest risk of death was among those who'd received cancer treatment within the past three months.

And the type of therapy mattered: Patients treated with immunotherapy plus chemotherapy faced the highest risk of dying after contracting Covid-19.

Experts stressed that the findings should not deter cancer patients from getting lifesaving or life-prolonging treatment.

"We don't want people delaying care," said lead researcher Dr Trisha Wise-Draper, an oncologist at the University of Cincinnati Cancer Center. "The cancer is more deadly than Covid."

Instead, she said, the findings offer more insight into which patients are at greatest risk of becoming severely ill should they contract Covid-19.

CORONAVIRUS CASES LATEST

SA cases update: 

The latest number of confirmed cases is 681 289.

According to the latest update, 16 976 deaths have been recorded in the country.

There have been 614 781 recoveries.

So far, nearly 4.27 million tests have been conducted, with 18 113 new tests reported.

Global cases update:

For the latest global data, follow this interactive map from Johns Hopkins University & Medicine.

Late on Sunday night, positive cases worldwide were more than 35.01 million, while deaths were more than 1.03 million.

The United States had the most cases in the world - more than 7.41 million, as well as the most deaths - more than 209 000.

HEALTH TIPS (as recommended by the NICD and WHO)

• Maintain physical distancing – stay at least one metre away from somebody who is coughing or sneezing

• Practise frequent hand-washing, especially after direct contact with ill people or their environment

• Avoid touching your eyes, nose and mouth, as your hands touch many surfaces and could potentially transfer the virus

• Practise respiratory hygiene – cover your mouth with your bent elbow or tissue when you cough or sneeze. Remember to dispose the tissue immediately after use.

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