In search of the Delta Variant


By Orlando Pulido
As the experience of Countries with sophisticated health systems is now showing, it is better to be prepared for the detection of any COVID-19 variant. As of February 1, 2021, Belize’s Ministry of Health and Wellness was preparing itself for any appearance of COVID-19 variants that are now de-stabilizing health systems in other regions of the World. The Ministry of Health has a plan in place should any variants be detected.
Belize had partnered with Baylor College in Houston in February 2020 where they were holding three hundred swabs. Baylor College’s report on the swabs was forthcoming. The Caribbean Public Health Agency CARPHA also had ten swabs from Belize during that same time. Much specialized equipment is needed to do the gene sequencing to discover whether the COVID-19 virus has mutated to a considerable degree as to become a public health concern.
With almost every person it infects, the COVID-19 virus changes very subtly – picking up a letter in its genetic code here, another being deleted there or swapped for something different. These occur usually because of tiny errors as the virus takes over the cell’s molecular machinery to copy itself. Most have little effect other than helping scientists to trace how the virus is spreading around the world. But occasionally a mutation occurs that alters how quickly the virus spreads, how infectious it might be or even the severity of the disease it causes.
Over a year after the global COVID-19 pandemic started, the issue of mutations looms large. New variants capable of spreading faster are emerging and leading to inevitable questions about whether they will make the newly approved vaccines less effective.
The oily capsule that surrounds most of the COVID-19 virus is studded with these spikes sticking outwards, making it look like a crown when viewed through an electron microscope. It is this appearance that gives the coronavirus family its name – corona is Latin for a crown. The spikes are also the main way COVID-19 recognizes the cells it can infect and helps the virus penetrate them.
Early in its existence, COVID-19 gained an ability that would prove decisive in its relationship with human beings. The virus picked up a seemingly small change in its genetic code. It was likely an unfortunate accident – a fragment of genetic information from another virus got muddled up with that of the coronavirus while they were both infecting a bat.
Included within this tiny piece of genome, however, were the instructions that altered a key part of the virus – its spike protein. This change to COVID-19’s spike protein meant it could hijack an enzyme found in the human body called furin. This enzyme acts like a pair of molecular scissors, normally cutting open hormones and growth factors to activate them. But when furin snips part of the COVID-19 spike protein, which is normally folded in a series of loops on the outside of the virus, it opens like a hinge.
“This exposes a new sequence in the spike protein,” says Yohei Yamauchi, a reader in viral cell biology at the University of Bristol, UK, who has been studying how this change may have led COVID-19 to become more infective in humans. “It is one of the changes that make this virus different from previous coronaviruses that caused Sars and Mers.”
This new mutation meant COVID-19 could suddenly latch onto an important molecule found scattered around the outside of human respiratory cells called Neuropilin 1. This molecule helps to transport material inside cells and deeper into tissues – the mutation was like handing COVID-19 the keys to a new door into our cells and meant the virus could replicate in greater numbers in the human airways.
Although this mutation was just one in COVID-19’s short existence, it proved to be important. Some researchers believe it may be one of the key mutations that allowed the coronavirus to jump species and begin causing a rapidly spreading disease in humans. But almost as soon as it did this, it began picking up other mutations.
One such mutation result is The Delta variant, which is now causing concern internationally. First identified in India, this more transmissible form of the novel coronavirus has spread to at least 77 countries and regions and now makes up more than 20 percent of all U.S. cases. The Centers for Disease Control and Prevention has identified it as a “variant of concern.” If vaccination rates fail to keep pace with its spread, experts say, the variant could lead to new COVID surges in parts of the country where a substantial proportion of the population remains unvaccinated.
Studies to date suggest the Delta variant is between 40 and 60 percent more transmissible than the Alpha variant first identified in the U.K.—which was already 50 percent more transmissible than the original viral strain first detected in Wuhan, China. Delta has quickly become the dominant variant in the U.K. and has led to another surge in cases there, despite the population’s high vaccination rate.
“It is the most hypertransmissible, contagious version of the virus we’ve seen to date, for sure—it’s a superspreader strain if there ever was one,” says Eric Topol, a professor of molecular medicine and an executive vice president at the Scripps Research Institution.
There is some indication that the Delta variant may also result in more severe disease. A study in Scotland, published in the Lancet, found the hospitalization rate of patients with that variant wasabout 85 percent higher than that of people with the Alpha variant. But because of the time lag between hospitalizations and deaths, there is not enough data to say whether or not Delta is more deadly than other variants.
Fortunately, vaccination appears to provide good protection against Delta—although one dose seems to offer less protection than it did against other variants. A preprint study by Public Health England found that two doses of the Pfizer-BioNTech vaccine and two doses of the AstraZeneca vaccine were 96 percent and 92 percent effective, respectively, at preventing hospitalization in people infected with Delta. That result is comparable to the level of protection seen against other variants. Meanwhile, a single dose of the AstraZeneca vaccine was only 71 percent effective against hospitalization caused by Delta (a single dose of Pfizer was still 94 percent effective), and one shot of either vaccine was only about 33.5 percent effective against symptomatic COVID from that variant, highlighting the importance of getting both doses.
Experts say the Delta variant poses a relatively low threat to fully vaccinated people. “You should not worry at all” if you have had two doses of the Pfizer-BioNTech or Moderna vaccine, Topol says. Less is known about how well the Johnson & Johnson vaccine protects against the Delta variant. And immunocompromised people still need to be somewhat careful even if they are vaccinated because they may not have developed strong immunity from the vaccine.
Meanwhile; the World Health Organization is urging people to continue wearing a mask and social distancing—even if they are fully vaccinated against COVID—amid the spread of Delta. While most COVID vaccines are thought to largely protect against all known variants, none is 100 percent effective.
The WHO also advises vaccinated people to keep taking precautions such as staying in well-ventilated areas and avoiding crowds. “This still continues to be extremely important, even if you are vaccinated, when you have a community transmission ongoing,” said Mariângela Simão, the WHO’s assistant director-general of access to medicines and health products, in a recent news briefing.
“What we’re saying is once you’ve been fully vaccinated, continue to play it safe because you could end up as part of a transmission chain,” added Bruce Aylward, senior advisor on organizational change to the WHO’s director-general.
The Center for Disease Control’s guidance for unvaccinated people continues to be that they should wear a mask in public indoor settings and follow other public health precautions, such as distancing and keeping to well-ventilated spaces. Whenever it comes to the Delta variant, prevention is better than cure.