The true origins of the current surge

Much has been made about why the country is going through yet another COVID surge. Many have argued that it’s simply because of un-vaccinated individuals, but that is based mainly on who is hospitalized, not who is spreading the infection.

Of interest, the surge seems to be affecting mainly areas of the U.S. that didn’t have large outbreaks of infection during the summer. As most of these areas are in the North and the West, with the South spared, this makes it appear there is some type of seasonality to this outbreak. But again, the exact source of the infectious surge hasn’t been fully defined.

Michigan is leading the current surge and is suffering from the highest per capita rate of infections in the country. Fortunately, there is data about where the current infections are coming from in Michigan. That data suggests involvement of non-immunized individuals, but more importantly specific situations where COVID-19 spreads very rapidly.

Michigan has a significantly high adult vaccination rate, which approaches 71%. But there are significant caveats here. This rate only reflects first doses of vaccine, and fully vaccinated individuals account for only 59% of the adult population. Importantly, this only identifies those over 16 years of age. The entire younger population has just recently been approved for the vaccine and is less than 5% vaccinated.

Note the new (top table) and ongoing (bottom table) infection outbreaks the last week in Michigan are predominantly in schools and nursing facilities. From the Michigan COVID-19 website.

The State’s monitoring has documented that the major sources of COVID-19 outbreaks are in K-12 schools, childcare programs, and nursing homes. It is not surprising that many of the current outbreaks are in schools, since essentially none of these individuals is immunized. In addition, as weather has cooled, the students spend more time together indoors. School Halloween parties have become particularly implicated. Infected children bring the virus home and infect their parents, especially if they also are not vaccinated. This appears to be the major source of infections.

Nursing homes are a bit more complex. While most residents were vaccinated early in the year, the staff in many facilities remains significantly unvaccinated and have rates similar to the rest of the state. This suggests potentially 40% of the staff aren’t immunized. Also many of the residents are now 10 months out from their Pfizer vaccine and have decreasing immunity.  This population accounts for most of the breakthrough infections that require hospitalization.

Once unvaccinated individuals are infected by children, they are much more likely to be hospitalized. This has led to the health care systems in Michigan being overwhelmed (see above). The hospital admission figures for the Henry Ford health system and Spectrum Health in Michigan document the high ratios of vaccinated to unvaccinated individuals who are admitted to these centers. This truly is a hospital epidemic of the unvaccinated.

We need to vaccinate children to prevent these infections. The good news is that recent studies from the CDC show the COVID-19 vaccines are very effective in children (above). This should lead to better control of COVID.

DC data on efficacy of COVID-19 vaccine in adolescents. This should end hospitalizations and reduce transmission to others.

Eventually anyone who refuses to be vaccinated will be infected with COVID-19 and either die or develop some immunity. Until then, unvaccinated people will continue to be infected, get ill, and overwhelm hospitals. COVID-19 may become endemic, with scattered outbreaks throughout the year, but as the Southeast U.S. has shown sooner or later this pandemic will end. 

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

4 thoughts on “The true origins of the current surge

  1. Dr. Baker: What’s the current evidence regarding how contagious a triply (2 mRNA shots + a booster) vaccinated person is to others if they test positive, but are asymptomatic? Should they change their behavior around others?
    If so, for how long? And do the health and risk factors of the other people factor in?

    All that I’ve seen about contagiousness is that it increases after vaccination (https://www.nature.com/articles/d41586-021-02689-y).

    Thanks.

    Like

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