Coronavirus survivors are likely to be immune to the disease for six months - whether they have antibodies or not, Sweden's top epidemiologist claims
- Anders Tegnell says he hasn't seen a person be infected with Covid-19 twice
- The controversial expert led Sweden through the pandemic without a lockdown
- He said even without antibodies someone is protected for at least half a year
- Evidence suggests people also develop T cells which are more long-lasting
Coronavirus survivors are likely to have immunity against the disease for six months, Sweden's top epidemiologist has claimed.
Dr Anders Tegnell, who has guided the nation through the pandemic without calling for a lockdown, says he hasn't seen evidence of people getting infected twice since the start of the pandemic in December 2019.
Even if a survivor doesn't develop antibodies — immune cells that remember how to fight the virus — they will be protected, he believes.
Evidence is starting to show that antibodies aren't the only type of immunity against Covid-19, and that T cells also play an important role.
It's hoped T cells, which target and destroy cells already infected, would offer long-term protection — possibly up to many years later.
But scientists do not have any firm proof as to how long immunity actually lasts once a person has fought off Covid-19, mainly because it is still shrouded in secrecy and has only been known to exist since the start of the year.
Anders Tegnell, Sweden's top epidemiologist, claimed coronavirus survivors are likely to have immunity for six months. He was speaking at a press conference yesterday (pictured)
Dr Tegnell's comments about immunity lasting for half a year were made at a press conference in Stockholm yesterday, The Telegraph reports.
He said: 'The risk of being reinfected and of transmitting the disease to other people is probably very close to zero.
'Therefore, we think you can meet other people, even if they are in a high-risk group. We don't see cases of people falling ill twice from Covid-19.
'Hence, our assessment is if you do get Covid-19 you are immune, even if you don't develop antibodies.'
There have been cases of people getting infected more than once but they have failed to convinced scientists that humans only get a short-lived immunity against the disease.
Some infectious disease experts say it is just an issue with testing because old viral fragments that are not contagious are picked up by swabs taken weeks or months after a patient first became ill.
Dr Tegnell did not explain what proof he had to back-up his claims that immunity lasts for six months.
Scientists are hopeful any protection will last for longer, perhaps many years. Protection against some viruses, like chickenpox, is life-long.
Until now most of the attention on immunity has focused on antibodies, substances made by the immune system to fight off a virus before it takes hold.
These are the proteins that antibody blood tests screen for, revealing if you have or haven't had the disease.
But focus has largely shifted towards T cells in recent weeks — a type of white blood cell in the immune system that is harder to detect with testing.
Leading immunologists have said T cells are typically more durable and long lasting than antibodies.
A slew of papers in recent weeks have discussed that T cells play a significant role in fighting infection with other coronaviruses — including ones that cause the common cold.
And in one coronavirus closely related to the one that causes Covid-19, called SARS, survivors have shown to have effective T cells 17 years after recovery.
T cells may be produced by everyone that has had the coronavirus, from mild to severe cases, Danny Altmann, a professor of immunology at Imperial College London has said.
T cells are considered one of the first line of defenses, and may clear the virus before antibodies are kicked into action.
This may explain why it takes at least four weeks for antibodies to show up in a Covid-19 survivors blood, or never at all if antibodies weren't needed in the first place.
The Karolinska Institutet and Karolinska University Hospital, in Sweden, showed that many people with mild or asymptomatic Covid-19 demonstrate so-called T-cell immunity to the disease, even if they have not tested positive for antibodies to the virus.
But because there is no rapid commercial test to spot them circulating in the body, it is not possible to use them as a marker of infection in the population.
If it were, it may reveal that far more people have some form of immunity against the disease than antibody testing suggests — possibly double, according to experts at Karolinska.
Generally, scientists do not know how long immunity lasts, given that the SARS-CoV-2 has only existed since December 2019.
If they did, it could help speed up vaccine development because scientists would have a benchmark for immunity levels.
Dr Tegnell, who previously said the 'world went mad' with coronavirus lockdowns, said last night Sweden's strategy for slowing the epidemic, which has been widely questioned abroad, was working.
Unlike most European nations, Sweden never imposed a lockdown and kept schools for under-16s, cafes, bars, restaurants and most businesses open. Masks have been recommended only for healthcare personnel.
Dr Tegnell said a rapid slowdown in the spread of the virus indicated very strongly that Sweden had reached relatively widespread immunity.
'The epidemic is now being slowed down, in a way that I think few of us would have believed a week or so ago,' he said.
'It really is yet another sign that the Swedish strategy is working.'
Sweden's death toll stands at 5,646. But when compared relative to population size, it has far outstripped those of its Nordic neighbours.
It has one of the highest death tolls per capita in the world, at 558 fatalities per million people compared to Norway's 47.
But it remains lower than in some European countries that locked down, such as Britain (667) and Spain (607).
Grim projections from Sweden's health agency suggests the country could see another 5,800 coronavirus deaths, double its current toll, despite the peak passing in mid-April.
The agency noted that this was a possible scenario where 'infectivity increases quickly due to people for example socialise more frequently,' but would then decrease 'when people become aware of the outbreak and follow recommendations on distancing.'
In the mildest scenario presented, in which the spread of the virus follows current trends, just over 200 additional deaths were expected.
Most watched News videos
- Incredible drone footage of Charmouth Beach following the rockfall
- Brits 'trapped' in Dubai share horrible weather experience
- Crowd chants 'bring him out' outside church where stabber being held
- 'He paid the mob to whack her': Audio reveals OJ ordered wife's death
- Murder suspects dragged into cop van after 'burnt body' discovered
- Shocking scenes at Dubai airport after flood strands passengers
- English cargo ship captain accuses French of 'illegal trafficking'
- Chaos in Dubai morning after over year and half's worth of rain fell
- 'Inhumane' woman wheels CORPSE into bank to get loan 'signed off'
- Suella Braverman hits back as Brussels Mayor shuts down conference
- Shocking moment school volunteer upskirts a woman at Target
- Appalling moment student slaps woman teacher twice across the face