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Infectious Diseases

20 September 2020

Coronavirus science | Week in review: 'Long Covid', obesity, and will the virus become seasonal?

Recap of the latest coronavirus research and science: Recovered patients struggle; obesity and the immune system's response; and will Covid-19 become seasonal?

LATEST SCIENCE AND RESEARCH

READ | 'Long Covid': Clinics could be our future as recovered patients struggle with after effects

For some Covid-19 patients, the effects linger long after recovery.

Colloquially called "long Covid", some people who have recovered from Covid-19 are suffering from health issues like chronic fatigue, heart difficulties, breathing problems, and even a decline in mental health. Basically, the longer-term effects of Covid-19 are unknown, as we're still in the throes of the pandemic.

Even children – who generally have mild reactions to the virus – might face long-term health effects indirectly linked to the disease.

Research from Austria showed lung and heart damage weeks after recovery, although there appeared to be some self-recovery after a longer period of time, highlighting the importance of pulmonary rehabilitation for hospitalised patients.

According to a Nature article, research yet to be published arrived at similar findings, seeing scarring on lungs more than a month later in a third of a 33-patient cohort. While these were severe cases, the overall rate of this kind of lung damage is expected to be 10% of total infections. On a global scale, that's, however, still hundreds of thousands of people that have to deal with new health issues and disabilities.

READ | The immune system's response to Covid-19 may be altered by obesity

The severity of Covid-19 is generally mediated by the human body's immune response. Everyone's immunity is different – which is why reactions to the virus are so varied – and there are various genetic, environmental and chronic disease factors that can influence this response.

One such factor is obesity. Those who have a BMI of more than 40 are 2.6 times more likely to die from a coronavirus infection.

A new study published by Endocrine Society investigates how this condition exacerbates inflammation in the body, which, in turn, puts strain on the immune system.

Early studies of the virus took place in China, and there was no focus on obesity because it is so rare in that country. But that changed when the virus hit the US, a country with one of the highest rates of obesity in the world.

South Africa also has a high rate of obesity, making it important to understand the interaction between Covid-19 and obesity.

READ | Will Covid-19 become seasonal like influenza?

Even though influenza caused global devastation back in 1918, we don't nowadays regard “the flu” as a deadly disease – although it can still make some people very ill.

One hypothesis that's been doing the rounds since the beginning of the outbreak, is that Covid-19 might become a seasonal occurrence.

A new review, recently published in Frontiers in Published Health, states that Covid-19 might become seasonal in countries with temperate climates, but only when there is herd immunity.

But until then, Covid-19 will continue to circulate across seasons and, in the absence of a vaccine, public health measures such as masks and stringent hand hygiene will need to be applied to contain the virus.

According to Dr Hassan Zaraket, senior study other from the American University of Beirut in Lebanon, Covid-19 is here to stay and will continue to cause outbreaks all year, until herd immunity is achieved.

READ | Antibody responses in Covid-19 patients: What latest study reveals

A new comprehensive analysis of antibody responses in Covid-19 patients showed that the neutralising activity of antibodies from the recovered patients was typically not strong, and declined sharply within one month of hospital discharge.

Researchers Chao Wu and Rui Huang, of Nanjing University Medical School in China, monitored the SARS-CoV-2-specific antibody responses in 19 non-severe and seven severe Covid-19 patients for seven weeks from disease onset.

They wrote that the results of their study, published in PLOS Pathogens this month, may serve as fundamental information for developing a Covid-19 vaccine, as well as effective treatments for the disease.

Neutralising antibodies, as explained in a previous Health24 article, is an important line of defence in the fight against Covid-19. They do their job by binding to specific parts of the virus, and neutralise the virus’s damaging effects.

If antibodies are found to be present, they indicate that the person has previously had a SARS-CoV-2 infection (as the antibodies are only produced by infection), and that if that same person encountered the virus again, the presence of antibodies would likely result in a level of protection.

READ | The latest science confirms - strict physical distancing lowers the chance of contracting Covid-19

A new study by a team of researchers at the Johns Hopkins Bloomberg School of Public Health suggested that using public transport, visiting a place of worship or otherwise travelling from the house was associated with a higher chance of testing positive for SARS-CoV-2.

Their study was published on 2 September 2020 in the journal Clinical Infectious Diseases and surveyed a random sample of more than 1 000 participants in Maryland in late June.

The participants were all asked about their physical distancing practices, whether they use public transportation, their SARS-CoV-2 infection history and anything else that might contribute to Covid-19 risk.

Perhaps the most important finding of the survey, was that those who frequently used public transport were more than four times more likely to test positive for SARS-CoV-2, while those who practised strict outdoor physical distancing where only a tenth as likely to test positive.

Looking at all the variables, the researchers concluded that spending more time in public places was more strongly associated with a history of SARS-CoV-2 infection.

CORONAVIRUS CASES LATEST

SA cases update: 

The latest number of confirmed cases is 659 656.

According to the latest update, 15 940 deaths have been recorded in the country.

There have been 589 434 recoveries.

So far, more than 4.02 million tests have been conducted, with 21 069 new tests reported.

Global cases update:

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

Early on Sunday morning, positive cases worldwide were 30.66 million, while deaths were close to 955 000.

The United States had the most cases in the world - more than 6.76 million, as well as the most deaths - more than 199 000.

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.

Image credit: Getty Images