The Chinese practice of variolation must have made little sense to 18th-century Englanders. It involved giving children small scratches and then rubbing the broken skin with powder ground from smallpox scabs.
The resulting mild infection protected most children against the full-blown disease (though it killed some too). Variolation — so named because smallpox is spread by the variola virus — was the first step towards the safer practice of vaccination.
The fact that a theory is counter-intuitive does not necessarily mean it is wrong. It does, however, demand that those championing it explain carefully why they think it is better than the common sense alternative. The UK government, having initially adopted a more laissez-faire management style to coronavirus than other European countries, has found itself in a bind — although more draconian measures are being announced on an almost hourly basis.