A STORY of Bloomberg last August 15 made me sad and depressed because the much touted ‘herd immunity’ (as if it were a promised land for humanity) will never materialize and looks more like a ‘fantasy’ now.
The thinking then was the given the protection from vaccines against the virus for majority of the population of a given area, herd immunity will protect those vaccinated leaving the unvaccinated to fend for themselves or the survival of the fittest mode in the jungle of virus and its variants.
The thinking was that the pandemic would ebb and then mostly fade once a chunk of the population, possibly 60 to 70 percent, was vaccinated or had resistance through a previous infection.
But new variants like delta, which are more transmissible and been shown to evade these protections in some cases, are moving the bar for herd immunity near impossibly high levels, Bloomberg said.
Widening outbreaks
Delta is spurring widening outbreaks in countries like the US and UK that have already been walloped by the virus, and presumably have some measure of natural immunity in addition to vaccination rates of more than 50 percent.
It’s also hitting nations that have until now managed to keep the virus out almost entirely, like Australia and China.
This month, the Infectious Diseases Society of America estimated that delta had pushed the threshold for herd immunity to well over 80 percent and possibly close to 90 percent.
Public health officials like Anthony Fauci have drawn controversy by shifting the goalposts over the past year, increasing the number of people who need protection before hitting herd immunity.
Meanwhile, vaccine hesitancy and supply issues mean most countries won’t get close to even the original numbers.
“Will we get to herd immunity? No, very unlikely, by definition,” said Greg Poland, director of the Vaccine Research Group at the Mayo Clinic in Rochester, Minnesota.
Even a vaccination rate of as high as 95 percent wouldn’t achieve it, he said. “It is a neck and neck race between the development of ever more highly transmissible variants which develop the capacity to evade immunity, and immunization rates.”
Not Nature
Nature isn’t going to solve the problem, either. It’s unclear how long natural immunity gained by surviving Covid-19 will last, and whether it will be effective at fighting off new strains.
Future variants, including some that could evade immunity even more efficiently than delta, raise questions about how – and when – this will be over.
“If it was as simple as getting the infection once means you are immune for life, that would be great, but I don’t think that’s the case,” said S.V. Mahadevan, director of South Asia Outreach at the Center for Asian Health Research and Education at Stanford University Medical Center. “That’s a troubling problem.”
Newer strains
Already there are signs that some people, and some places — like Brazil and other countries in South America — are being battered a second time by newer strains.
Without herd immunity, the virus could linger for decades in some form, possibly forcing the world’s most powerful nations to adjust their diverging strategies on opening borders and economies.
Countries like China that have pursued tight Covid-Zero policies by attempting to wipe out every infection, may eventually have to consider a looser stance. Others like the US and UK which have opened up despite a resurgence in the virus run the risk of wave after wave of infection, the article noted.
Not quick fix
Vaccines so far haven’t been the quick fix some had hoped for. Israel, among the most vaccinated countries in the world, has already started administering booster shots, amid evidence that the current immunizations aren’t offering the protection that was hoped.
The most powerful vaccines, including the mRNA shots from Pfizer Inc., BioNTech SE and Moderna Inc., would make it easier to get high levels of immunity since they are so effective. Yet breakthrough infections are possible with even these shots.
The benefits of other approaches, including those made by China’s vaccine manufacturers, AstraZeneca Plc and Johnson & Johnson, may offer even less protection.
False narrative
Herd immunity is a real thing, protecting much of the world against viral threats from the measles to polio.
Scientists credit it for helping eradicate smallpox. Having it as a goal likely helped the world embrace measures like wearing masks and social distancing. But it also created a false narrative.
“The focus on ‘herd immunity’ has, in my view, been quite damaging,” said William Hanage, an epidemiologist and expert in communicable disease dynamics at the Harvard T.H. Chan School of Public Health. “It presents people with an unrealistic vision of how the pandemic comes to a close and doesn’t account for the evolution of either the virus or the nature of disease in reinfections.”
Some countries learned the shortfalls of herd immunity the hard way. UK Prime Minister Boris Johnson originally planned to use it as a primary approach to Covid-19, suggesting some of his constituents could “take it on the chin” with natural infections before the magnitude of the damage became apparent.
Others are now throwing in the towel, with Indonesia most vocally leading the way. The world’s fourth-most populous nation determined that it would be impossible to stop the virus even if everyone in the country was immunized. It’s redoubling its efforts to promote mask wearing and social distancing, while continuing to boost its vaccination rate.
Meanwhile, Singapore and Australia are easing into opening, promising they will do so as they hit sufficiently high vaccination levels.
The End
Despite evidence that it will be difficult or impossible to reach herd immunity, many public health officials aren’t willing to give up on it. Governments worldwide are focusing on widening inoculation programs.
Yet the individualistic approach by many countries, and vaccine shortages, are contributing to the global problem. The risk will remain for everyone for so long asa nation is experiencing massive outbreaks.
2022 at the earliest
The world is unlikely to put the pandemic behind it until 2022 at the earliest, experts say. That target could be push back if the virus mounts another metamorphosis to become even more transmissible or even better at evading resistance.
There is hope for new vaccines and other approaches that could stop transmission more dramatically, but none of those are in human trials yet. It will be a few years before this is a real possibility.
Regardless, the end may not come via herd immunity. Instead, the virus has a high likelihood of remaining entrenched globally, causing outbreaks that are hopefully mitigated partly by vaccinations, masking, and other interventions.
“Delta is not something we will be able to eradicate,” Hanage said. “Even Alpha would have been hard. However with sufficient immunity, ideally achieved by vaccination, we can expect it to become a much milder illness.”
Revisiting 1918
The Spanish flu of 1918 may show how Covid may play out, the Mayo Clinic’s Poland said. It’s likely that variants will continue to emerge, forcing the use of boosters or routine immunizations, targeted to the newer strains.
“Then, if we are lucky, what is likely to happen is that this will become something more akin to influenza, where we will always have it,” Poland said.
“It’ll become more seasonal, just like the coronaviruses that are already circulating, and we will just have to keep immunizing.” If things do play out like the flu, the world may have some version of Covid-19 a hundred years from now.
Singapore’s thrust
In a recent story I wrote, Singapore which has the world’s highest inoculation rate is now preparing to open and live with COVID-19 just like flu.
Singapore, a country of 5.7 million people, had only 44 COVID-19 deaths since January 2020 and the world’s highest vaccination rate.
It is reopening for business and is laying the groundwork to live with the virus just as it does with common diseases like influenza which kills 800 in a typical year, according to doctors interviewed by Reuters.
Its medical experts say residents may see hundreds of deaths each year from endemic COVID-19, just like flu.
That pragmatic approach could set an example for other countries looking to exit lockdowns as they ramp up their own inoculation programs.
As of Aug. 16, 80 percent of those aged 70 years and older had been fully vaccinated, and those 60 to 69 were at 88 percent.
Singapore reported six COVID-19 deaths in the last two weeks, none of whom were vaccinated.
Early results from mathematical models suggest that the expected number of deaths from seniors aged 60 and above will be about 480 in 2022, said Teo Yik Ying, dean of the Saw Swee Hock School of Public Health at NUS.
Other nations that had early successes with the virus, such as Australia, are also shifting their strategies to brace for more COVID-19 deaths in an era where the disease is here to stay.
Don’t sulk
Whether or not we reach herd immunity, we must not sulk. Let us just keep on with our discipline and vigilance in protecting ourselves by always wearing the face masks, (as for face shields I honestly do not believe if there is a science to it, but I follow just the same), social and physical distancing and constant personal hygiene (particularly handwashing).
This bit of news may be depressing and may augment our causes of mental illness, but it is better to know the truth than to be blank about scientific realities about our world.
After all, public health crises are part of the climate change impacts we are experiencing each day and the only way to reverse it is to do our share in mitigating climate change and reducing our carbon footprints.
Cheer up! The world has not ended yet.