Recent petitions from two groups of scientists conflict over herd immunity.
The Great Barrington Declaration
On 4 October 2020, three public health experts launched the “Great Barrington Declaration”, a petition calling on governments to protect the vulnerable and allow the young and healthy to live their lives without restrictions. This group says it has grave concerns about the damaging physical and mental health impacts of the prevailing Covid-19 policies.
Older people would be offered home delivery of groceries and other essentials. Visits would be done outdoors and testing would be available for those who wanted to visit. Free N95 masks would also be provided. And workers in their 60s would work from home or take paid sabbatical.
Nursing home staff and visitors that are not already immune would be frequently tested and infected individuals would not be sent to nursing homes. All new nursing home residents would be tested and infected residents would be isolated from the other residents.
Under this strategy a large healthy percentage of the population would live without restrictions, eventually become infected with SARS-CoV-2, recover with natural immunity, and then be unable to contract and spread the disease to anyone else. The virus would eventually run out of steam as it struggled to find new hosts, a phenomenon known as herd immunity. Eventually the vulnerable would no longer be at high risk of the disease. However, the virus would continue in endemic form with low rates of infections.
The authors do not encourage intentionally exposing anyone to the virus. However, they see herd immunity as the only long term outcome and believe it is not worth suffering the negative consequences of standing in the way of the spread of the disease.
The John Snow Memorandum
On 14 October 2020, another group of scientists launched a petition, partly in response to the Great Barrington Declaration, called the “John Snow Memorandum”, named after a British physician considered a founder of modern epidemiology.
These scientists do not view herd immunity as the only long term outcome. Instead they describes SARS-CoV-2 herd immunity as “a dangerous fallacy unsupported by scientific evidence” and urge governments to focus on suppressing community spread of the virus until therapeutic treatments and vaccines can be deployed in the coming months.
The infection fatality rate of Covid-19 is several-fold higher than that of seasonal influenza and infection can lead to persisting illness, including in young, previously healthy people.
They say there is no clear evidence that infected people develop durable immunity. They say the duration of immunity is unknown at this stage.
On the question of natural immunity, Dr. Gupta of the Great Barrington Declaration says if Covid-19 is like other coronaviruses natural immunity would be 5-10 years. However, this is at odds with research. One study found that seasonal coronavirus reinfection frequently occurs after 12 months. Another study gives a range between 6-12 months. For the SARS-CoV-1 virus, immunity was common up to 2 years. But those researching SARS-CoV-2 immunity are reluctant to draw any conclusions on immunity at this stage.
In addition, the John Snow Memorandum group says that identifying the vulnerable is highly problematic. For example, Long Covid sufferers, many of whom experience initially mild symptoms, are often young and healthy. This vulnerable group, some of whom still struggle with daily tasks and are unable to return to work, is currently impossible to identify before they are infected. A now largely house bound 37-year old doctor, who published her story in the NY Times, has a form of Long Covid that she believes she might never recover from.
The John Snow Memorandum group also says if there is no lasting protective immunity, a strategy that does not suppress community spread would not end the pandemic but result in recurrent epidemics, as was the case with numerous infectious diseases before the advent of vaccination. Such a strategy is more likely to overwhelm hospitals and place an unacceptable burden on the economy and health-care workers, many of whom have died from Covid-19 or experienced trauma as a result of having to practise disaster medicine.
Furthermore, they argue that prolonged isolation of large swathes of the population is practically impossible and unethical. Empirical evidence from many countries shows that it is not feasible to restrict uncontrolled outbreaks to particular sections of society.
Finally they say protecting economies is inextricably tied to controlling Covid-19. The economic impacts have often been worse in countries that were not able to use the time during and after lockdown to establish effective pandemic control systems.
The names of five researchers in Switzerland are among the roughly 4,000 signatories published on the John Snow Memorandum website. Christian Althaus from the University of Bern, Isabella Eckerle at the University of Geneva, Ilona Kickbusch from the Graduate Institute of International and Development Studies in Geneva, Emma Hodcroft at the University of Basel and Jacques Fellay at the University Hospital Lausanne have all signed it,
No signatories from Switzerland are among the names of the 42 published on the Great Barrington Declaration website.