First the bad news.
By March, the COVID-19 virus may spread 50% faster thanks the arrival of a new strain first detected in England in September. The strain doesn’t cause more serious illness — but spreads must faster, including among children.
The federal Centers for Disease Control predicts that the new strain will displace the existing strains all across the country by March. Even that prediction is based on the optimistic assumption that this month we’ll start vaccinating a million people every day and that between 10 and 30% of the population will have has acquired immunity by surviving an infection.
This means we’re in a footrace with the new strain — and off to a slow start.
No doubt. That’s bad — especially since the virus has Arizona surrounded — with cases detected in California, New Mexico, Utah and Colorado. The new strain may already be circulating in Arizona as well. However, the U.S. does such limited genetic sequencing of COVID-19 strains that perhaps we just haven’t yet detected it locally.
Arizona had the nation’s fastest rate of spread of the virus last week, which might mean the problem strain has already arrived. Gila County’s infection rate per 100,000 this week stood at 83, compared to statewide average of 101. Apache county’s rate has fallen to 73 but Navajo County is still at 105.
Expect those number to climb again once the new strain gets loose in Arizona.
But wait — we promised good news.
The new vaccines should still work against the new strain, according to laboratory tests.
That would be more reassuring if the mass vaccination rollout effort wasn’t going so slowly — with maybe 40% of the doses so far distributed by the federal government actually administered. However, lab tests suggest the Moderna and Pfizer vaccines both work just as well against the new strain as the current, dominant strains.
Moreover, the evidence right now suggests that masks, social distancing, avoiding groups, washing hands and other measured urged by public health officials will still effectively slow the new strain until mass vaccinations provide herd immunity sometime this summer.
This leaves the question of the children.
Early evidence from England suggested children were more likely to spread the new strain than the previously dominant strains. This prompted Great Britain to shut down its schools and return to distance learning.
Additional studies have suggested that the new strain does spread faster among children — but still only half as fast as it spreads among adults. Moreover, the new strain’s no more likely to cause serous illness among children than do the existing, dominant strains.
Contact tracing in Great Britain involving 20,000 people infected with the new strain included 3,000 children, according to the study by Public Health England. Young children were half as likely to spread the virus as adults. The same thing holds true for existing strains. Teenagers spread the virus less readily than adults — but much more easily than younger children.
Most European countries now facing the spread of the new strain have not shut down their schools — although they face far less spread than the U.S. Moreover, European countries have have kept their schools open have taken more precautions than most U.S. schools. They have generally required students and staff to wear masks and kept children in pods to limit how much they mingle. Elementary schools pose an especially low risk of creating new clusters, since the virus spreads more slowly and causes fewer problems among younger children.
The sudden cluster of mutations in new strains of the virus has unsettled epidemiologists. Some experts believe the new strain might have incubated in a single patient who was ill for an extended period of time. The virus therefore had time to evolve over time and respond to the attacks of the immune system. This might have been supercharged by early efforts to treat patients with blood plasma from other patients, adding in antibodies to the virus from a number of patients. This might have supercharged the new strain’s evolution. However, at this point that’s just the speculation of the experts, based on repeatedly doing a genetic sequence on the viruses in a patient in England who was sick for months before dying. Some of the same mutations have shown up in different strains all over the globe.
The new strain has 17 key mutations in the intricate genetic instructions that code for the 29 proteins that make up the virus. The changes in the 30,000 “letters” of RNA instructions have made the virus better at breaking into cells and evading the attacking antibodies of the immune system.
Viruses all continually evolve and adapt to the response of the immune systems. For instance, the flu virus changes its outer covering so quickly that the virus manufacturers modify the vaccine every year, based on the dominant strains in circulation. Other viruses change so slowly that the same vaccine formulation remains effective for years — even decades.
Fortunately, despite the spurt of change in the new strain, the current vaccines appear to remain highly effective, with few side effects.
No one’s sure why children remain so resistant — both to the initial infection and then to serious side effects if they do get infected.
Their resistance likely stems from characteristic of their immune systems, as well as other key factors, according to a summary of the research from Nature, a peer-reviewed scientific journal.
Children have fast-acting immune systems that respond quickly to new viruses. Older people devote more of their immune system effort to developing immune system T-cells that remember viruses from past exposures. Something in the speed of the response among children coupled with their inexperienced T-cells apparently marshals a response so quickly that the virus has a harder time getting a foothold.
In addition, children breathe in much less air per lungful — which might mean they get a smaller dose when exposed. Their noses also have fewer ACE2 receptors, which is one of the types of cells COVID latches onto an infects.
Finally, children are much more exposed to the common cold – which is also caused by a coronavirus. Perhaps that exposure to a far less harmful relative of COVID-19 leaves their immune systems better prepared.