I will continue the series of posts on healing relationships, but I think we have enough information about the omicron variant of SARS-COV-2 to spend some time talking about it. In this post I will discuss infectivity, vaccine resistance, and some prevalent misinformation which continues to complicate rational measures to combat the virus.

Infectivity

First a little review on epidemiology. Those of you who want a more complete review can look at my previous post Epidemiology Made Simple. The potential infectivity of any virus or bacteria is described by a number called R₀. R₀ is the average number of other people that one infected person infects. R₀ for the original SARS-COV-2 virus detected in Wuhan, China was about 2.5. That means that on average one infected person infected between two and three other people. The delta variant of SARS-COV-2 has an R₀ of about 7. That means that on average one person infected with the delta variant infects 7 other people. The delta variant is almost three times as infectious as the original virus!

So far it looks like the omicron variant has an R₀ of about 10. To put that in perspective, the most infectious virus that we know of is the measles virus. It has an R₀ of 13. That means the omicron variant is almost as infectious as measles. That is why it is spreading so fast. Cases in the U.K. where omicron is predominant are doubling every two to three days! That makes it almost impossible to limit the spread by contact tracing.

R₀ refers only to the potential infectivity of the virus in people who have no immunity. This potential infectivity can be reduced by measures that either increase immunity (such as vaccination or previous infection) and/or that limit the spread of the virus in people such as masking, social distancing and avoiding small, poorly ventilated indoor spaces.

Effectiveness of vaccines for omicron

Effectiveness of vaccines is measured two ways. First is the effectiveness of the vaccine in prevention of infection in the first place. Second and much more important is the effectiveness of the vaccine in preventing hospitalization and death.

Omicron has more than thirty mutations in the spike protein. This means that it looks very different from the original virus isolated in Wuhan. The previous definition of fully vaccinated was two immunizations. Those people who had two vaccinations had about 70% protection from infection with the delta variant, but so far in the U.K. it looks more like 10% protection from omicron infection. Protection from being sick enough to be in the hospital, though is still very good, even without a booster. Having a booster gives about 80% protection from symptomatic infection and about 99.9% protection from hospitalization and death.

Does the omicron variant cause milder disease?

It is too early to be sure about that. Hospitalization rates for people infected with the omicron variant are lower so far, but that is in countries such as the U.K. with very high vaccination rates, or like South Africa that has high numbers of people who have had COVID previously. We don’t yet know the hospitalization rate for the unvaccinated, but hospitalizations are starting to go up in the U.K. and in much of the U.S. What we can say so far is that the omicron variant does not seem to cause more severe disease, but that is all we can say at this point. Because omicron is so contagious, we will see huge increases in case numbers and therefore hospitalizations no matter what the severity of illness omicron causes.

What about children?

There have been a number of articles in the press recently about hospitalizations going up for children with COVID. While that is true, the numbers are still tiny compared to hospitalizations for adults. Children are still at substantially lower risk of symptomatic infection even with the omicron variant. That does not mean that they don’t get infected at all, just that their infections are much more likely to have no symptoms. In a recent large antibody study in Texas (more about this later) a third of the children in the study showed evidence of previous COVID. Over half of those children had no history of any symptoms at all. That is good news for the children, but bad news for adults exposed to them. It appears that infected children without symptoms could be major spreaders of COVID.

Vaccines protect children five to twelve years old as well as they protect adults. The only serious side effect for children is mild inflammation of the heart called myocarditis. This occurs in about one in one million doses, almost never requires hospitalization and goes away by itself.

There has been a great deal of misinformation about the risk of vaccination in children. A U.S. virologist, Dr Robert Malone, has posted a video claiming that the spike protein fragments created by the vaccine are toxic and cause damage to multiple organs in children. This is utterly false. Millions of children have received the Pfizer vaccine and there is not one shred of evidence that there is any organ damage other than the mild transient myocarditis that occurs in one in a million.

Is having had and recovered from COVID as good protection as having a vaccine?

There definitely is some protection from having COVID in the past. It is not as good as protection from the vaccine though, and it tends to wane more quickly than protection from the Pfizer or Moderna vaccine. In the Texas study that I mentioned earlier, called Texas Cares, the University of Texas Health Science Center recruited over 87,000 people in Texas ages 8 to 80. I was a participant in that study. Every participant filled out a survey asking about symptoms of COVID and dates of vaccinations. Then blood was drawn at a local lab at baseline and every 3 months for two more times. The survey was repeated before each blood draw.

Two antibody tests were done on each sample. One test measured the N antibody. People who were positive for N antibody had COVID at some previous time. The other test measured antibodies to the SARS-COV-2 spike protein. The spike protein antibodies are the neutralizing antibodies that protect you from severe illness with COVID. People who had only the spike protein antibody had been vaccinated but had never had COVID. The preliminary results were recently published. What they found was that spike protein antibodies in unvaccinated people with a previous infection peak at 120 days after infection and then decrease. Unvaccinated people with a previous infection overall had lower levels of spike protein antibodies than people who were vaccinated. People who had a previous infection and were vaccinated had the highest levels of spike protein antibodies.

As an example I will use my own data from this study as well as the data from a friend who had COVID but had not been vaccinated. My initial spike protein antibody level was over 300. His was 30. Three weeks after my booster of the Pfizer vaccine I went for the second blood draw. My spike protein antibodies at that blood draw were over 2,500.

This study clearly suggests that COVID vaccines give better protection than previous COVID infection and that boosters cause a big increase in neutralizing antibody. The combination of previous COVID infection and vaccination gives the best protection of all.

Should I wear a mask even if I am vaccinated and boosted?

The omicron variant is so contagious that even vaccinated and boosted people could still get infected even though that infection is likely (but not guaranteed) to be mild. My personal feeling (and the CDC recommendation) is that everyone should continue to mask indoors in public places, like grocery stores, department stores or any other public place indoors where multiple people not known to you congregate. U.S. made N-95 masks are now readily available and provide much better protection than cloth masks.

Bottom Line

The omicron variant is extremely contagious, almost as much as measles. Vaccines, especially with a booster give 80% protection from symptomatic infection and 99% protection from hospitalization and death. Children frequently get infection without symptoms and may serve to spread infection to others. Vaccinating children five to twelve is safe and effective. Having had a COVID infection in the past gives some protection but is less than protection from vaccines. Because omicron is so contagious N-95 masks should be worn in indoor public places regardless of vaccination status.