Coronavirus: No scientific evidence that group immunity works
Wednesday, 18 March 2020
The World Health Organisation recommends a package of comprehensive measures to beat the coronavirus. Allowing a majority of the population to be infected to create group immunity is not one of them.
WHO’s staff are now working remotely as a social distancing measure due to the coronavirus. At yesterday’s press briefing at an empty office building in Copenhagen, dr Hans Kluge, WHO regional director for Europe, explained that the outbreak is progressing at different speeds in different countries depending on demographics and other factors.
“Europe is the epicenter of the first pandemic of coronavirus and every country, with no exceptions, need to take their boldest actions to stop or slow the virus spread. Boldest action should include community action. Thinking that ‘this does not concern me’ is not an option,” he said. “The good news is that Europe is alert and on guard.”
He listed “Four Cs” scenarios of the outbreak: no case, first case, first cluster and first evidence of community transmission. The basic actions in each scenario are the same, but the emphasis changes depending on which transmission scenario a country is in.
“Every country must assess their own situation and context including virus spread, measures in place and social acceptability and adopt the most appropriate interventions.”
“We are fortunate that across Europe many countries now have national response plans with efficient multi-sectoral measures and strong laboratory testing capacity. The experience of China and others shows that testing and contact tracing, combined with social distancing measures and community mobilization, when put in place quickly and effectively can prevent infections and save lives.”
Many countries in Europe have reached the fourth scenario, with increases in the number of infected persons that might overwhelm their health care systems. They are facing tough choices with consequences for the economy and public health. To win time, the infection curve must be flattened.
One of the questions asked to the WHO experts yesterday (17 March) was about their opinion about the group or herd immunity approach. Briefly, this approach assumes that if a majority of the population will become infected, most will also recover and become immune. The rest of the population, who have not been infected until then, will be spared and cannot be infected.
The Dutch government seems to rely on scientific advice saying that if 60 % of the population has been infected and recovered there will be enough group immunity for the whole population. In a speech to the nation on Monday evening, prime-minister Mark Rutte, said it was almost inevitable that this would happen.
If group immunity can be built up slowly, there is no need to completely lock down a country. The most important thing right now is to buy time and flatten the curve by social distancing, teleworking and other measures. Stefan Löfven, the Swedish prime-minister, seems to argue in the same way.
United Kingdom, however, changed its mind and started to implement similar measures as in other countries after realising that the group immunity approach might result in hundreds of thousands of deaths.
Dr Richard Pebody emphasized the need of a mixed approach with focus on containment and suppression of the coronavirus to buy time. His colleague dr Dorit Nitzan was more outspoken and replied that WHO has not enough evidence about the group immunity approach. “This is a new virus and we don’t know enough about it to conclude that it can cause immunity.”
But the Netherlands has faith in their own experts. The country is pursuing maximum containment but without a 100% lockdown.
Dr Hans Kluge finished by saying that he was pleased to see that United Kingdom had returned to “mainstream” and started to implement basic measures to contain the spread of the virus.