Silver lining of Hepatitis A: asthma prevention?

I strongly suspect there are many as-yet-undiscovered -- or simply misunderstood -- viruses which confer significant survival benefits: saluviruses. (See my previous discussion here, here, and here.)

Now, the BBC reports research indicating that once someone has recovered from a bout with the disease-causing Hepatitis A virus, they may be spared future asthma.

In this case, it's unlikely that the virus has inserted a lingering genetic capability. Rather, the immune system is left, in the infection's aftermath, better calibrated to ignore transient environmental irritants. For example, previous research has suggested that each of the following suppress asthma...

• Intestinal worm infections
• Exposure to dirt and benign bacteria
• Minor viral infections

Meanwhile, antibiotic use in infants may promote asthma -- perhaps by forestalling the immune system's own self-calibration against minor infections.

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