(CNN) First coronavirus death in Europe, with more than 67,000 cases globally,  features an interview with Kent and Rebecca Frasure, quarantined on the  cruise ship Diamond Princess. Print interview at  (Intelligencer) An American on Quarantined Cruise Ship Describes Moment His Wife Was Diagnosed With Coronavirus.

Despite what we expect as intimate contact on the cruise, Kent has not contracted COVID-19.  By itself, this registers as no more than an oddity. With that taken care of, Indonesia’s claim of zero  native cases (ABC, First case of corona virus linked to Bali after report Chinese tourist returned positive test). is no more than carelessness combined with wishful thinking.

But is it? If confirmed by more  instances, the explanations are limited to three:

• Some people are genetically more susceptible than others.
• Some groups have cultural practices that protect.
• There are in circulation, one or more corona viruses with overlapping serotypes.

The serotype is the face the virus presents to the immune system. Viruses can share serotypes, either partly or completely, yet have different characteristics of infection. The common rabies virus is one example. Half a dozen common strains  have different clinical courses, but one vaccine is good for all.

The most famous case is smallpox. In 1796, Edward Jenner, a British physician, et al., promoted the fact that  immunity to smallpox was produced by inoculation with the live cowpox virus.

So there is precedent: a zoonosis immunizes against a human disease.  In Indonesia, a sero-similar virus could be endemic as a local version of the common cold. It could have developed by spontaneous mutation. But are there live animal markets in Indonesia?

Yes, there are. (Animals Asia) Animals Asia Ambassador Peter Egan visits “sickening horrors” of Indonesia’s brutal dog and cat meat markets. But domestic animals are not the historic reservoirs. Bats are more to the point. (ABC Australia) Coronavirus scare prompts call to pause bat meat consumption from Indonesian market.

The picture clarifies. With bats, dogs, and cats, civets and snakes are probably in the mix. A specialty coffee, kopi luwak, is made from beans in civet poop. Human processors of this material are exposed to a constant stream of civet viruses.

So a benign relative of COVID-19 may be present in the Indonesia community. Prior infection may produce the implied  immunity of Indonesians. Immunity caused by a live virus tends to be stronger and last longer than vaccine-induced.

Medical ethics has developed to protect the public from the worst abuses of the past. But it may have taken a turn towards avoiding liability. A simple thought experiment is Jenner’s smallpox vaccine.  Is there a modern path of ethical approval, save from a movie zombie attack, that would allow Jenner’s primitive vaccine, which worked?

It’s not hypothetical. The prospects for third world countries, and war zones, are dismal, unless they have their own fortuitous zoonosis. The analysis problem is not hard. It involves comprehensive sampling of circulating corona viruses in Indonesia, searching for similar serotypes.

There is a preliminary report from China that serum from recovered patients may be useful. A serum from “boosted” Indonesians could be a valuable export.  Or planeloads of sneezy Indonesians could fly to third-world destinations, and meet-and-greet, spreading benign relatives of COVID-19. See (bioRxiv ) Increased frequency of travel may act to decrease the chance of a global pandemic

You may be of conservative mind, rightly observing that you could lose your job with this.  For passive inclinations, there is still work. Detection or absence sero-similar relatives of COVID-19 in world populations offers refined estimates of the ultimate cost.