The head of the WHO has warned against pursuing herd immunity as a strategy to stop the pandemic, describing the idea as 'simply unethical.'
The idea that letting the virus circulate will eventually reap benefits has been touted by those opposed to lockdowns, but Tedros Adhanom Ghebreyesus said 'herd immunity is achieved by protecting people from a virus, not by exposing them to it'.
'Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak,' Tedros said.
He added that some diseases such as measles need as many as 95 per cent of people to be protected for herd immunity to develop, whereas the WHO estimates that less than 10 per cent of the world's population has any immunity to Covid-19.
However, the WHO has also voiced scepticism over blanket lockdowns, calling for a 'middle way' between lockdown and the unrestricted spread of the disease.
'We in the World Health Organization do not advocate lockdowns as the primary means of control of this virus,' said Dr David Nabarro, a special WHO envoy for Covid-19, last week.
Dr Nabarro said in an article called 'Reflections About the Middle Path' that 'lockdowns just freeze the virus in place, they do not lead to elimination'.
'From time to time it will be necessary briefly to restrict movement locally to enable suppression of outbreaks,' he said.
But he added that 'building public health capacity is not the same as implementing lockdowns. It is about building up the capability of public health services to interrupt transmission in localities'.
Herd immunity is achieved when so many people are immune that the virus will not spread through the population, protecting even those who are still susceptible.
The idea caused controversy in Britain in the spring when the UK government initially adopted lighter measures than much of Europe, hinting at a herd immunity strategy, before eventually changing course and going into lockdown.
Sweden, which did reject lockdown, has also suggested it could develop herd immunity while saying that this is not its main objective.
However, a study in May - amid the first wave of the pandemic - found that only 7.3 per cent of people in hard-hit Stockholm had developed antibodies.
Tedros said that too little was known about immunity to Covid-19 to know if herd immunity is even achievable.
He added that governments usually achieve herd immunity with vaccines, which are still in development for the coronavirus.
'We have some clues, but we don´t have the complete picture,' he said of immunity to Covid-19.
Tedros noted that the WHO has documented some instances of people becoming re-infected with coronavirus after recovering from an initial bout of the virus.
On Monday, doctors reported that a man in Nevada had tested positive for coronavirus a second time in June after previously having it in April.
The second infection was 'symptomatically more severe than the first', they wrote in medical journal The Lancet.
However, cases like this this have been rare in comparison to the total of more than 37.4million infections around the world.
Tedros said that while most people appear to develop some kind of immune response, is unclear how long that lasts or how robust that protection is.
'Allowing a dangerous virus that we don´t fully understand to run free is simply unethical,' he said.
WHO estimates less than 10 per cent of the population has any immunity to the coronavirus, meaning the vast majority of the world remains susceptible.
Tedros also noted countries had reported record-high daily figures of Covid-19 to the UN health agency for the last four days.
A resurgence of virus cases in Europe has led to alarming numbers in Britain, Germany and Italy in recent days, with Spain and France already in a second wave.
A group of researchers who looked at European figures said in June that 'no country has yet seen infection rates sufficient to prevent a second wave of transmission'.
'The herd immunity argument is therefore at odds with both mortality data' and figures on the spread of the disease, they said.
No comments:
Post a Comment