In recent weeks, Nepal has resumed nationwide vaccinations against the Covid virus in earnest. While this is a crucial step towards ending the pandemic – with only 7.34% of the population fully vaccinated, we are not out of the woods yet, not by a long shot.
Leaked information from the US Center for Disease Control last week has added renewed complications in this fight against Covid-19.
The Delta variant was the dominant strain in Nepal, and caused more than 200,000 reported infections across the country within 30 days between May and June 2020. This has now become the main strain of the virus on the planet.
Evidence now suggests that it is more transmissible than the viruses that cause MERS, SARS, Ebola, the common cold, the seasonal flu, and smallpox. This is one of the most effective virus variants to face modern society, spreading as effectively as the ubiquitous (but mostly harmless) chickenpox.
When the Delta variant was first isolated, the global public health community understood that it transmitted more effectively, but many questions remained about whether or not it was more deadly or likely to cause serious complications.
One of the first sources about the severity of Delta included a study from Scotland which demonstrated that it was about twice as likely to result in hospitalisation for unvaccinated individuals than the original Alpha variant.
Another analysis of 38,805 cases in England revealed that the Delta variant posed a 2.61 times higher risk of hospitalisation than Alpha.
One reason for this faster spread is a mutation on the spike protein, which the virus uses to enter human cells. The Delta variant has a particular mutation called ‘D614G’(colloquially referred to as ‘Doug’) that packs the surface of the virus with spike proteins which, in turn, help it avoid the natural antibodies that human cells use for defenseand enter our cells more easily.
As if this wasn’t enough, Delta also has a spike mutation called P681R, which appears to produce higher viral loads in patients, making it easy to spread to more people, more quickly. A study in China demonstrated that people infected with Delta have 1,000 times more viruses in their respiratory tract.
This means that there is more Covid virus per droplet that we expel. People exposed to the smaller droplets with higher concentrations of virus can be infected more quickly and when standing much further away from one another.
This makes the virus much more likely to spread between people even with very limited contact: a review of CCTV footage from a shopping mall in Sydney, Australia proved that the virus was transmitted between two persons who were only casually passing by.
Delta has an incubation period of only four days, rather than six. This means that people are contagious sooner and end up infecting more people. A patient with the original Alpha variant would infect, on average, two or three other people. With Delta, this number soars to an average of eight.
The good news is that vaccinations still offer significant protection against the Delta variant. While there is mounting evidence breakthrough infections do occur, and may result in death, the chances of ending up in the hospital or a morgue are vastly reduced once you’ve had a full dose.
The bad news is that even if you are fully vaccinated, you can still be a major spreader of the virus. A Public Health England study of more than 365,000 households found that full vaccination with either Pfizer or AstraZeneca was associated with only a 40 to 50% reduction in household transmission after a vaccinated person tested positive.
The leaked documents from the CDC go so far as to suggest that the likelihood of further transmitting the virus is nearly the same for vaccinated and non-vaccinated individuals. This is particularly worrying for Nepal given that full vaccines for the majority of the population – including children in particular – are still a long ways away.
Today, despite an increasing number of people receiving vaccinations, Delta has the upper hand. We cannot expect our government to take adequate and timely steps to avoid a third or fourth deadly wave of infections, and we can expect the virus to continue to mutate and find even more effective ways to continue to circulate through the global population. Ensuring the safety of ourselves and our communities is, once again, left in our own hands.
The standard practice of regular handwashing and wearing face masks is no longer sufficient to prevent the spread of COVID.
With Delta, the most important prevention behaviour is to avoid crowded public spaces — particularly when there is poor air ventilation. A vaccine is not a passport to resume life as normal.
Indeed, the data shows that we all need to change our behavior immediately and with a renewed vigour, and to amend our public messaging accordingly. If we fail to do so, the virus will win and more loss of life and prolonged, stricter lockdowns will be the inevitable result.
Sushil Koirala is a public health expert based in Bangkok, Thailand.
Ben Ayers is an American citizen based in Nepal for over 20 years.