POST 158. May 5, 2021. CORONAVIRUS. . As populations get closer to herd immunity “ it may be helpful to introduce some nuance to what we mean by the term. Nationwide herd immunity. Regional herd immunity. Temporary herd immunity. Endemicity.”

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“Early in the pandemic, when vaccines for the coronavirus were still just a glimmer on the horizon, the term “herd immunity” came to signify the endgame: the point when enough Americans would be protected from the virus so we could be rid of the pathogen and reclaim our lives.

Now, more than half of adults in the United States have been inoculated with at least one dose of a vaccine. But daily vaccination rates are slipping, and there is widespread consensus among scientists and public health experts that the herd immunity threshold is not attainable — at least not in the foreseeable future, and perhaps not ever.

Instead, they are coming to the conclusion that rather than making a long-promised exit, the virus will most likely become a manageable threat that will continue to circulate in the United States for years to come, still causing hospitalizations and deaths but in much smaller numbers.

How much smaller is uncertain and depends in part on how much of the nation, and the world, becomes vaccinated and how the coronavirus evolves. It is already clear, however, that the virus is changing too quickly, new variants are spreading too easily and vaccination is proceeding too slowly for herd immunity to be within reach anytime soon.

Continued immunizations, especially for people at highest risk because of age, exposure or health status, will be crucial to limiting the severity of outbreaks, if not their frequency, experts believe.

“The virus is unlikely to go away,” said Rustom Antia, an evolutionary biologist at Emory University in Atlanta. “But we want to do all we can to check that it’s likely to become a mild infection.”

The shift in outlook presents a new challenge for public health authorities. The drive for herd immunity — by the summer, some experts once thought possible — captured the imagination of large segments of the public. To say the goal will not be attained adds another “why bother” to the list of reasons that vaccine skeptics use to avoid being inoculated.

Yet vaccinations remain the key to transforming the virus into a controllable threat, experts said.

Dr. Anthony S. Fauci, the Biden administration’s top adviser on Covid-19, acknowledged the shift in experts’ thinking.

“People were getting confused and thinking you’re never going to get the infections down until you reach this mystical level of herd immunity, whatever that number is,” he said.

“That’s why we stopped using herd immunity in the classic sense,” he added. “I’m saying: Forget that for a second. You vaccinate enough people, the infections are going to go down.”  (A)

“What I really worry about is that those people who are already on the fence don’t get vaccinated (and) we don’t reach herd immunity come the fall,” CNN medical analyst Dr. Leana Wen told CNN.

“And then with the winter … we have a big resurgence, maybe we have variants coming in from other countries, and we could start this whole process all over again and have another huge pandemic come the winter.”

Experts including Dr. Anthony Fauci have estimated between 70% to 85% of the US population needs to be immune to the virus — through vaccination or previous infection — to control its spread…

Some experts think driving down infections will be good enough, even if herd immunity isn’t reached.

While it would be unfortunate for the United States to not reach herd immunity, most people will still be able to get back to their pre-pandemic lives if case numbers continue to fall, Dr. Ashish Jha, dean of the Brown University School of Health, told CNN on Monday.

“We may not get to zero, we probably won’t,” Jha said. “But if we can get the infections at very low levels, most of us can get back to our lives in normal ways. I think we can probably live with that.”

For the ongoing local, state and federal efforts to get more shots into Americans’ arms, now comes the hard part: reaching audiences that weren’t as eager to get vaccinated in the past few months or who may not have had access to a shot.

“We need to be … innovative around both culturally competent education and be thoughtful about where the holes are and where we can get shots in people’s arms,” infectious diseases expert Dr. Mati Hlatshwayo Davis told CNN over the weekend.

‘Make it really easy’ to get vaccinated, doctor says

New strategies to increase vaccinations must be tried, such as closing mass vaccination centers and distributing vaccine to more localized venues such as doctors’ offices, churches, schools and workplaces, Wen said.

The government should “make it really easy” for people to get vaccinated, Wen said, especially Americans who aren’t really vaccine hesitant but just can’t find the time because of jobs and family responsibilities….

New Jersey Gov. Phil Murphy said the state plans to put its efforts “into overdrive” to get more residents vaccinated, including allowing walk-up vaccinations to anyone over the age of 16 at the state’s six vaccine megasites at specific hours.

The state also will launch a vaccine awareness initiative that will include a “massive” email campaign and automated outgoing calls, Murphy said.

In a campaign dubbed “Shot and a Beer,” the state plans to offer a free beer to anyone over the age of 21 who shows their completed CDC vaccination card at thirteen participating breweries throughout the state, Murphy said.

In Florida, Gov. Ron DeSantis signed an executive order Monday suspending the remaining power of local governments to implement or enforce Covid-19 restrictions.

“I think that’s the evidence-based thing to do. I think folks that are saying they need to be policing people at this point, if you are saying that, you really are saying you don’t believe in the vaccines, you don’t believe in the data, you don’t believe in the science,” DeSantis said at a news conference in St. Petersburg.” (B)

“As COVID-19 vaccination rates pick up around the world, people have reasonably begun to ask: how much longer will this pandemic last? It’s an issue surrounded with uncertainties. But the once-popular idea that enough people will eventually gain immunity to SARS-CoV-2 to block most transmission — a ‘herd-immunity threshold’ — is starting to look unlikely.

That threshold is generally achievable only with high vaccination rates, and many scientists had thought that once people started being immunized en masse, herd immunity would permit society to return to normal. Most estimates had placed the threshold at 60–70% of the population gaining immunity, either through vaccinations or past exposure to the virus. But as the pandemic enters its second year, the thinking has begun to shift. In February, independent data scientist Youyang Gu changed the name of his popular COVID-19 forecasting model from ‘Path to Herd Immunity’ to ‘Path to Normality’. He said that reaching a herd-immunity threshold was looking unlikely because of factors such as vaccine hesitancy, the emergence of new variants and the delayed arrival of vaccinations for children.

Gu is a data scientist, but his thinking aligns with that of many in the epidemiology community. “We’re moving away from the idea that we’ll hit the herd-immunity threshold and then the pandemic will go away for good,” says epidemiologist Lauren Ancel Meyers, executive director of the University of Texas at Austin COVID-19 Modeling Consortium. This shift reflects the complexities and challenges of the pandemic, and shouldn’t overshadow the fact that vaccination is helping. “The vaccine will mean that the virus will start to dissipate on its own,” Meyers says. But as new variants arise and immunity from infections potentially wanes, “we may find ourselves months or a year down the road still battling the threat, and having to deal with future surges”.

Long-term prospects for the pandemic probably include COVID-19 becoming an endemic disease, much like influenza. But in the near term, scientists are contemplating a new normal that does not include herd immunity. Here are some of the reasons behind this mindset, and what they mean for the next year of the pandemic.” (C)

“How many people are already immune to SARS-CoV-2?

The short answer is that we don’t know. Study results released on April 27 suggest that 21% of New York City residents have antibodies to SARS-CoV-2, meaning they had likely been exposed to the virus. In most other places, these numbers are lower. For example, in testing done on April 3-4 in Santa Clara County, California, 3% of residents had these antibodies.

These studies used tests that look at antibodies, because antibodies are an easily detected measure of immune response and are sometimes an indicator of who is protected from infection. However, we do not know if people with antibodies to SARS-CoV-2 are immune—and if they are, how long any protection might last…

Ultimately, to know how many people are immune to SARS-CoV-2, we’ll need to know not only how many people have antibodies (a number that will increase in the coming months), but also how protective those antibodies are (so-called correlates of immunity). To know this, we need to make sure that existing antibody tests are high-quality, and we need to perform additional studies to evaluate whether having antibodies provides protection against reinfection.” (D)

Whether or not COVID-19 can be conquered through herd immunity is an open question, according to experts.

In an April 1, 2021, article in the Boston Globe, Marc Lipsitch, professor of epidemiology and director of the Center for Communicable Disease Dynamics at Harvard T.H. Chan School of Public Health, was among experts who said that a lack of clear data on the virus and vaccines makes it hard to determine the possibility of reaching herd immunity, which could occur if enough people are vaccinated or otherwise immune to the virus.

There’s a simple math formula for calculating herd immunity. But the problem is that one of the figures needed for the formula is a disease’s infectiousness rate—and scientists aren’t sure what that rate is.

Early in the pandemic, scientists thought that each infectious person with COVID-19 would infect 2.5 to 3 other people—meaning that reaching herd immunity would require roughly two-thirds of a population to be immune, according to the formula. But that estimate may be off. Many early cases may have been missed because of limited early testing for COVID-19. And because people have changed their behavior over time, it may have masked the disease’s true infectiousness. “We were sort of stuck with bad data,” said Lipsitch.

Other factors further complicate the herd immunity calculation. One is the presence of highly infectious variants. Another is that it’s not known whether, and to what extent, vaccinated people can still transmit the disease to others.

If COVID-19 is more infectious than previously thought, the herd immunity threshold would be higher too. So, for instance, if each infectious person could infect four people, 75% of the population would need to be immune to stop the virus from spreading. If each person could infect five others, 80% would need to be immune; if they could infect six others, 85% would need immunity. (E)

“And while the prospect of the coronavirus dying out through a combination of vaccinations and herd immunity is appealing, the nation’s top doctor is urging caution.

Earlier this month, Dr. Anthony Fauci said in a White House briefing that, in the COVID-19 context, it’s difficult to define what exactly would constitute herd immunity.

“Rather than concentrating on an elusive number, let’s get as many people vaccinated as quickly as we possibly can,” Fauci said.” (F)

“To that end, America still has to do a lot more work to vaccinate people. The number of doses administered daily has declined in recent weeks to around 2.4 million on average from a high of nearly 3.4 million.

Experts attribute this to America’s vaccine rollout problem shifting from supply to demand. Brown University School of Public Health dean Ashish Jha used the analogy of a new iPhone coming out: So far, the US has vaccinated the most enthusiastic, those willing to camp out overnight for the vaccines. Now, the US has to make it less difficult for the less enthusiastic to get the shot — make it easier to get an appointment or remove appointment requirements entirely, and bring vaccines closer to where people are, including their homes, workplaces, doctor’s offices, or even hot spots for socializing and entertainment.

The US also may have to do work with those who are truly resistant. Based on public polls, that’s about 10 to 25 percent of American adults. The country could hit 60 percent of Americans or even 75 percent of adults without them. But converting as many of those people as possible still would help get the US there quicker. That could require extensive messaging efforts, especially from Republican leaders whose constituents are more likely to be hesitant.

If the US does all of this right, there’s genuinely good news: The end not only may be in sight, it’s perhaps even closer than we think.

“After going through this, people have a tendency to go crazy,” Kates said. “[People] are like, ‘Is this real? Are we really okay?’ The trauma is deep, so there’s a bit of anxiety about that. But I think we’re just in a much better place than we were not too long ago.”

“Monica Gandhi, M.D., an infectious disease doctor and professor of medicine at the University of California, San Francisco, says we will know we’re on the road to normalcy based on what’s happening in hospitals and in the community.

“We will know it when we see it,” she says. “First, hospitalizations will be massively reduced, because people can’t get severe disease after they’re immunized. Second, cases will be so low that even when people [have respiratory symptoms and] test, they won’t have it.”

Estimates of when we will reach that point are all over the map. Some experts predict a return to normalcy as soon as April or May, while others say it may not be until 2022.

The wide discrepancy reflects the reality that a range of complex factors could affect the timeline, in ways both good and bad. Here are four of the biggest variables that will determine when we can return to some semblance of normalcy.

1. The pace of vaccination

2. How long natural immunity lasts

3. More contagious virus variants

4. Vaccine hesitancy..

New normal will likely include the coronavirus

Wolfe, Gandhi, Mansky and Murray are all hopeful that some semblance of regular life will resume for Americans in the fall of 2021 or by early 2022 at the latest.

But they emphasize that the coronavirus will never be totally eradicated. It’s already spread too far, and it’s changing too fast. Instead, they said, the goal of public health efforts is to make it a manageable virus, like the seasonal flu. The vaccines authorized for use in the U.S. have been shown to be highly effective at reducing the number of severe COVID-19 cases and hospitalizations.

Depending on how long immunity from the vaccines last, we may need to get a coronavirus shot every year, or once every three years.

“The coronavirus will be with us, but it will not be terrible,” Gandhi says. “What’s important is that we don’t want to get severe disease. The vaccines mean that we can defang the virus, taking it from causing severe disease to a virus that causes a cold.” (G)

Reaching herd immunity with a vaccine is a little more complicated than it seems, though. Not everyone has the same risk of getting and passing on the virus—some are more likely to be infected and spread it (think: essential workers), while others may not have as high of a risk of passing it on (think: people who have been working from home and mainly staying indoors), Dr. Adalja says. “You may get the benefits of herd immunity before you actually cross the threshold of herd immunity if the people who are responsible for the majority of cases get vaccinated,” he says.

What happens after we finally reach herd immunity for COVID-19?

Doctors think COVID-19 will eventually be a smaller threat. “I doubt it will go away,” says Richard Watkins, M.D., an infectious disease specialist and a professor of internal medicine at the Northeast Ohio Medical University. He predicts that “COVID-19 will probably become seasonal, like the flu, with increases in the winter.”

Dr. Adalja also thinks COVID-19 will become “a much more manageable respiratory illness,” and anticipates that cases will drop. “They’ll be much lower, because the virus will have a harder time finding people to infect,” he says.

Finally, keep this in mind, per Dr. Adalja: “We should go back to some semblance of normalcy even before we reach herd immunity.”” (H)

“Herd immunity will represent a more definitive end to the pandemic. Isolated cases may still occur—indeed, the virus may continue to circulate for one or more quarters after herd immunity is reached. But with herd immunity, population-wide public-health measures can be phased out. As populations get closer to this state, it may be helpful to introduce some nuance to what we mean by the term.

Nationwide herd immunity. The full population is well protected so that the country experiences, at most, occasional small flare-ups of disease. This scenario is most likely in smaller countries where immunity to COVID-19 can become uniformly high.

Regional herd immunity. Some regions, states, or cities are well protected, while others experience ongoing outbreaks of COVID-19. In large, diverse countries like the United States, this situation is especially easy to imagine.

Temporary herd immunity. A population or region achieves herd immunity for some period, but as variants are introduced, against which prior immunity is less effective, a new wave of cases is launched. Another potential trigger for such a wave could come as immunity (particularly natural immunity) wanes. As the number of new cases of COVID-19 falls globally, the rate of emergence of important variants should also decrease, but some risk will remain.

Endemicity. A region fails to achieve herd immunity. Endemicity is most likely in places where vaccine access is limited, where few people choose to be vaccinated, if the duration of immunity is short, or variants that reduce vaccine efficacy are common and widespread. Endemicity might include cyclic, seasonal waves of disease, broadly similar to the flu, or a multiyear cycle of resurgence.

The next few years are likely to see a combination of some or all of these options around the world. Given the likely timing of herd immunity in various geographies and the uncertain duration of protection from vaccines (both duration of immune response and efficacy versus new variants), it is likely that some measures such as booster vaccines are likely to be required indefinitely. Herd immunity is not the same as eradication. SARS-CoV-2 will continue to exist. Even when a country reaches herd immunity, ongoing surveillance, booster vaccines, and potentially other measures may be needed.” (I)

PREQUELS

Post 32. June 16, 2020. CORONAVIRUS. Could the Trump administration be pursuing herd immunity by “inaction”?  “ If Fauci didn’t exist, we’d have to invent him.”

https://doctordidyouwashyourhands.com/2020/06/post-32-june-16-2020-coronavirus-could-the-trump-administration-be-pursuing-herd-immunity-by-inaction-if-fauci-didnt-exist-wed-have-to-invent-him/

POST 70. November 16, 2020. CORONAVIRUS. “White House coronavirus task force member Dr. Atlas criticized Michigan’s new Covid-19 restrictions..urging people to “rise up” against the new public health measures.

https://doctordidyouwashyourhands.com/2020/11/post-70-november-16-2020-coronavirus-white-house-coronavirus-task-force-member-dr-atlas-criticized-michigans-new-covid-19-restrictions-urging-people-to-rise-up-against-the-new-pub/

POST 81. December 1, 2020. CORONAVIRUS. “Dr. Atlas, … who espoused controversial theories and rankled government scientists while advising President Trump on the coronavirus pandemic, resigned…”

https://doctordidyouwashyourhands.com/2020/12/post-81-december-1-2020-coronavirus-dr-atllas-who-espoused-controversial-theories-and-rankled-government-scientists-while-advising-president-trump-on-the-coronavirus-pandemic/

POST 96. December 26, 2020. CORONAVIRUS. “Achieving herd immunity against the coronavirus could require as much as 90 percent of the population to be vaccinated, Anthony Fauci…”…”..he hesitated to state a number as high as 90% weeks ago because many Americans still seemed skeptical about vaccine….”

https://doctordidyouwashyourhands.com/2020/12/post-96-december-26-2020-coronavirus-achieving-herd-immunity-against-the-coronavirus-could-require-as-much-as-90-percent-of-the-population-to-be-vaccinated-anthony-fauci/

• A.Reaching ‘Herd Immunity’ Is Unlikely in the U.S., Experts Now Believe, by By Apoorva Mandavilli, https://www.nytimes.com/2021/05/03/health/covid-herd-immunity-vaccine.html
• B.Not reaching herd immunity by the fall could have dire consequences, medical expert says, By Ralph Ellis and Christina Maxouris, https://www.cnn.com/2021/05/03/health/us-coronavirus-monday/index.html
• C.Five reasons why COVID herd immunity is probably impossible, by Christie Aschwanden, https://www.nature.com/articles/d41586-021-00728-2
• D.COVID-19 AND THE LONG ROAD TO HERD IMMUNITY, By Hub staff report, https://hub.jhu.edu/2020/04/30/herd-immunity-covid-19-coronavirus/
• E.Can herd immunity stop COVID-19?, https://www.hsph.harvard.edu/news/hsph-in-the-news/can-herd-immunity-stop-covid-19/
• F.Hope for COVID-19 Herd Immunity Is Fading. Here’s Why, https://www.healthline.com/health-news/hope-for-covid-19-herd-immunity-is-fading-heres-why#A-global-pandemic
• G.When Will the Pandemic End and Life Return to Normal?, by Michelle Crouch, https://www.aarp.org/health/conditions-treatments/info-2021/when-will-covid-end.html
• H.How Close Are We to Herd Immunity for COVID-19?, By Korin Miller, https://www.prevention.com/health/a32209398/herd-immunity-coronavirus/
• I.When will the COVID-19 pandemic end?, By Sarun Charumilind, Matt Craven, Jessica Lamb, Adam Sabow, and Matt Wilson, https://www.mckinsey.com/industries/healthcare-systems-and-services/our-insights/when-will-the-covid-19-pandemic-end#https://www.mckinsey.com/industries/healthcare-systems-and-services/our-insights/when-will-the-covid-19-pandemic-end#