coronavirus immunity Archives - Iran News Daily

Early Immune Response May Result in Severe COVID-19

reporter 1222 — Mon, 24 Aug 2020 12:58:26 +0000

TEHRAN (Iran News) – Researchers may have come one step closer toward understanding how the immune system contributes to severe COVID-19.

In a study published in Science Immunology, researchers at Karolinska Institutet in Sweden show that so-called natural killer (NK) cells were strongly activated early after SARS-CoV-2 infection but that the type of activation differed in patients with moderate and severe COVID-19. The discovery contributes to our understanding of development of hyperinflammation in some patients, MedicaXpress reported.

SARS-CoV-2 infection can in some cases cause severe COVID-19 disease. Although this is thought to be partially driven by a misdirected innate immune response, many aspects of the early immune response to the infection remain elusive.

Researchers at Karolinska Institutet have now, in collaboration with colleagues at the Karolinska University Hospital, investigated the early response to SARS-CoV-2 infection of NK cells, a cell type in the immune system known to be important in the control of viral infections.

The study analyzed blood samples from 27 patients with moderate (10) and severe (17) COVID-19 infection. The researchers also included blood samples from 17 healthy individuals as a control group. The result showed that NK cells were strongly activated in the blood shortly after infection.

“The type of NK cell activation detected differed considerably in patients with moderate compared to severe disease,” says Niklas Björkström, physician and immunology researcher at the Center for Infectious Medicine, Department of Medicine Huddinge, at Karolinska Institutet, who led the study.

It is likely that the type of NK cell response observed in SARS-CoV-2 infected patients with moderate disease is a canonical NK cell response shared between many types of viral infections, according to the researchers.

However, patients who developed severe COVID-19 had a different composition of responding NK cells. These patients’ NK cells generally had higher expression of the proteins perforin, NKG2C and Ksp37, which according to the researchers reflect a high presence of so-called adaptive NK cells. Adaptive NK cells have an even greater ability to kill target cells compared to other NK cells.

The researchers are now investigating to what extent the NK cell-mediated immune response observed in the critically ill patients might contribute to COVID-19 severity, and the extent to which other parts of the response may be beneficial.

“Taken together, our findings provide additional insights into immune reactions in early SARS-CoV-2 infection and ensuing COVID-19 disease,” Niklas Björkström says. “We hope that these insights will contribute to the improved care and treatment of patients with severe COVID-19 disease.”

The study is part of the larger Karolinska COVID-19 Immune Atlas project, which aims to increase knowledge about the characteristics of immune cells in patients with COVID-19.

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Coronavirus Immunity Could Last Six Months

reporter 1222 — Sat, 23 May 2020 09:17:37 +0000

TEHRAN (Iran News) – People may only be immune to coronavirus for six months, a study said, raising questions over whether ‘immunity passports’ could be a route out of lockdown.

Researchers from the University of Amsterdam tested 10 men for four coronaviruses regularly over the course of 35 years.

The four coronaviruses cause the common cold and research said there was ‘an alarmingly short duration of protective immunity to coronavirus’, Times reported.

They said that after 12 months, people were frequently reinfected with the virus, and after six months the levels of antibodies substantially reduced.

Health Secretary Matt Hancock announced at the Downing Street briefing on Thursday that the Government has signed a contract for 10 million antibody testing kits.

He stressed the science of how people develop immunity and how long it lasts was still emerging.

He confirmed that ministers are already looking at a ‘system of certification’ that would signify people who are safe to go back to work and mix freely with others.

The University of Amsterdam researchers said that antibody tests to estimate how many people had been infected would become of limited use.

It comes as Oxford University began recruiting for large-scale trials for their coronavirus vaccine.

The study suggests people may have to get the jab annually to be immune to the bug.

The study has not yet been peer-reviewed and did not include women.

Professor Lia van der Hoek, one of the researchers involved in the study told The Times: ‘Herd immunity is an issue, even with vaccination, as it may be that people can get an infection again within six to 12 months. It is, however, uncertain what kind of disease is associated with reinfection by Sars-CoV-2, that is of course a big uncertainty.’

A virologist at Reading University Ian Jones added that other research suggests longer-lasting immunity as some only cause a mild disease which might not trigger great immunity.

He added that if the protection was partial it would be hard to score.

Hancock said: ‘We’re developing this critical science to know the impact of a positive antibody test and to develop the systems of certification to ensure people who have positive antibodies can be given assurances of what they can safely do.’

He added: ‘We’re not yet in a position to say that those who test positive in these antibody tests are immune from coronavirus.

‘But as our understanding of the disease improves, the insight these antibody tests provide will be crucial.’

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WHO: COVID-19 Survivors Not Having Immunity

reporter 1222 — Sat, 18 Apr 2020 08:41:32 +0000

TEHRAN (Iran News) – There is no evidence that people who have recovered from COVID-19 have immunity to the disease, the World Health Organization (WHO) said.

The UK government has bought 3.5 million serology tests – which measure levels of antibodies in blood plasma.

But senior WHO epidemiologists have warned that there is no proof that such antibody tests can show if someone who has been infected with COVID-19 cannot be infected again.

Many of the tests being developed are pinprick blood tests similar to instant HIV tests and measure for raised levels of the antibodies that the body uses to fight the virus.

Speaking at a news conference in Geneva, Dr. Maria van Kerkhove said: “There are a lot of countries that are suggesting using rapid diagnostic serological tests to be able to capture what they think will be a measure of immunity, Sky News reported.

“Right now, we have no evidence that the use of a serological test can show that an individual has immunity or is protected from reinfection.”

She added: “These antibody tests will be able to measure that level of seroprevalence – that level of antibodies – but that does not mean that somebody with antibodies means that they are immune.”

Dr. van Kerkhove said it was “a good thing” that so many tests are being developed, but said they will need to be validated “so that we know what they say they attempt to measure they are actually measuring”.

Her colleague Dr. Michael Ryan said the antibody tests also raised ethical questions.

He said: “There are serious ethical issues around the use of such an approach and we need to address it very carefully, we also need to look at the length of protection that antibodies might give.

“You might have someone who believes they are seropositive (have been infected) and protected in a situation where they may be exposed and in fact they are susceptible to the disease.”

He added that the tests had to be used as part of a coherent public health policy.

The WHO is due to issue updated guidance on the issue this weekend.

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