This is a COVID update. I’ll also briefly discuss a mystery from a few months ago, a hepatitis in children of unknown cause.

It’s been almost 3 weeks since my last post. Since then, we’ve seen remarkably little change in either infections or deaths in the US, California, or San Diego County.

Some scientists now argue that since so many who are newly infected test themselves with over the counter tests, hospitalization is really the new measure of how much COVID is in the population. In the US, BA.5 has caused hospital admissions to go from about 4000 to about 6000 per day.

BA.5 is more dangerous than previous Omicron versions because it replicates down deep in the lungs like the original Wuhan strain, Alpha, Beta, and Delta strains. Most Omicron strains were less dangerous because they replicate in the trachea, thus can’t cause pneumonia. BA.5 is now 80% of new infections in the US.

John Campbell has an interesting new video out about BA.5. He argues that while BA.5 reinfect those with previous infections, even Omicron, natural immunity does give substantial protection. Dr. Campbell is from the UK, so much of his data comes from the National Health Service, which as been doing a better job at publishing data than the CDC.

Campbell discussed a paper from Altarawneh et al that claims that only 15% of Britons have no previous infections. 55% of new BA.5 cases come from this 15%. That means that 45% of new BA.5 cases come form the other 85% of people who have no previous infections.

After doing all the math, the authors suggest that infection with a pre-Omicron variant is 28% effective at preventing infection with BA.5, and infection with a previous Omicron version was 79.7% effective against reinfection with BA.5. All this to say, if you’ve had COVID before, you are less likely to get BA.5, and will likely have less symptoms as well.

Hepatitis of unknown origin in children: A strange story came out earlier this year about dozens of children in a variety of countries that presented with hepatitis, or inflammation of the liver. The suddenness of onset and also the global nature suggested a widespread infectious disease. There was no correlation in cases with COVID or COVID vaccination. In some children, adenovirus was found. 18 children have died world wide from this hepatitis.

Adenovirus is a very, very common virus in humans. It’s so common in fact, that most of us catch when we are very young, and have no symptoms, which is why we don’t hear about it much. Some adenovirus infections can look like a common cold. Adenovirus does not cause hepatitis.

However, doctors recently discovered that all of the children tested were positive for an unusual virus called Adeno-associated virus-2. This weird virus can only replicate in a human that is already infected with an adenovirus. So this is an unusual case in which 2 simultaneous infections are required to cause disease. AAV2 appears to be the actual cause of hepatitis in children.

At this point, researchers believe that the lack of exposure to common pathogens during the lockdowns has lead to the result that many children do not have immunity to common viruses that they usually do. AAV2 hepatitis does not happen in adults because they already have immunity to Adenoviruses.

So what should you do if you have small children? Well at first, in my opinion, allowing a normal social schedule is likely a good idea at this point. Death rates from COVID are still low and have not really increased due to BA.5, so the risk to others is likely low. You may want to limit their contact those who are at high risk for COVID.

Also, if your child experiences any of the following, especially in combination, seek medical attention immediately, at least a phone call to your doctor:

Nausea
Abdominal pain
Vomiting
Diarrhea
Jaundice (yellowing of the skin)

Don’t fear, but be smart,
Erik