The pandemic will end, but the coronavirus is likely here to stay. here’s why – fr

The pandemic will end, but the coronavirus is likely here to stay. here’s why – fr

The COVID-19 pandemic has been a long and rocky road, and two words have come to symbolize its exit ramp: herd immunity.
Since the vaccine rollout began, public officials have stressed that vaccinating enough of the population will eventually stop the spread of the coronavirus. Every day, an online dashboard tracks San Diego County’s progress towards this goal.

But what happens once we reach it?

If you’ve been expecting the virus to go away, think again, says Natasha Martin, an infectious disease modeler at UC San Diego.

“The biggest misconception is that something magical, immediate and drastic will happen when we reach this level of immunity,” she said.

“It will come with a moan, not a bang. “

This is in part because we are already seeing the benefits of vaccination. Immunizing nearly the entire population against COVID-19 would help further, protecting both the vaccinated and the unvaccinated. But getting to this point will be difficult due to the rise in viral variants and issues of hesitation and access to vaccines. And we are already seeing a marked slowdown in the pace of deployment.

Martin and many others – including Dr Anthony Fauci, the country’s leading infectious disease specialist – say it’s even possible we’ll never quite achieve herd immunity. But they also say that continuing to vaccinate as many people as possible, as quickly as possible, will allow us to live safely alongside the virus by making infections less frequent and less severe.

In other words, the pandemic will end, but expect the coronavirus to stay.

Herd safety

Vaccines protect communities by depriving a virus of the one thing it cannot do without: hosts.

Viruses are basically tiny parasites. They sneak inside your cells, take them hostage, and create countless viral copies that spit out infected cells, often killing them in the process. And then they repeat this process over and over again.

If enough people have been vaccinated or have recovered from an infection, this leaves less room for a virus, which ends up breaking the cycle of transmission. And this point is known as collective immunity.

Collective immunity does not only help the vaccinated; it helps those who have not been vaccinated or who have been vaccinated but have not developed a strong immune response. This is because these people, who are still vulnerable to COVID-19, are now mainly in contact with immune people, who are much less likely to spread the virus.

“That person who is part of the herd but may not have received the vaccine or obtained full protection from the vaccine, they are also protected because the herd is protected,” said Dr. Davey Smith, head of the vaccine. UCSD infectious disease research.

These are not hypothetical and distant advantages of vaccination. They are already happening and have helped us reach a point where, on Monday, the county reported just 47 new cases, the lowest number since April 2020.

“I believe the reductions in case rates that we’ve seen recently are happening mainly because of the expansion of vaccinations,” Martin said.

But she warns that we still haven’t vaccinated enough people to avoid a potential resurgence in cases where everyone (especially the unvaccinated) suddenly ditched basic public health precautions.

Achieving herd immunity could prevent surges in a mask-less future. But how many people need to be vaccinated to get there? Martin’s best estimate is between 85% and 90%, maybe more.

These numbers apply to the entire population, which means about 3 million people in San Diego County are expected to be vaccinated or have recovered from COVID-19. This is far more than the county’s goal of fully immunizing 75% of San Diegans aged 12 and over, or about 2.1 million people.

Martin thinks that a higher goal is justified for several reasons. The first is that if children under 12 are not yet eligible for coronavirus vaccines, they can also contract COVID-19. Another factor is the increase in faster-spreading viral variants, particularly B.1.1.7, a strain first spotted in the UK and which now accounts for most new cases in the US. proved that this variant is transmissible from 40 to 50%.

It will take time to achieve these high levels of immunity at the community level, especially as the pace of vaccination has slowed. The number of San Diegans receiving their first dose of the vaccine has declined for six consecutive weeks, from around 123,500 per week in early April to nearly 60,000.

So far, 1.4 million residents have received the Johnson & Johnson single injection vaccine or both Moderna and Pfizer vaccines necessary for full immunity to the coronavirus. At the current rate, the county is unlikely to reach 2.1 million fully vaccinated San Diegans by their early July target, let alone the higher numbers Martin believes are necessary.

“We know it’s going to be a little tough,” Supervisor Nathan Fletcher said at the county’s weekly coronavirus briefing on Thursday. “We will continue to strive to achieve this goal. I think we’ll get there at some point. It’s more of an organizational tool that gives us something to strive for. “

No magic moment

Jaeden Johannesson, Ashley Skoglund and Emily Skoglund of Minnesota take a selfie near some sea lions in La Jolla on Tuesday, April 27, 2021 after the CDC said fully vaccinated people could go out without a mask except in crowded environments .

(Sandy Huffaker / For the San Diego Union-Tribune)

Regardless of when we cross that goal post, infection rates are unlikely to drop significantly. As more people congregate, the virus will be more likely to find those who have not been vaccinated. And a slow but steady vaccination compensated by people resuming their pre-pandemic activities will likely mean that case rates will continue to gradually decline, according to Smith of UCSD.

It is also likely that outbreaks will continue in places where vaccination rates are low. Models of infectious disease are based on population averages, which do not tell the whole story. If 85% of people have been vaccinated, it is unlikely that the remaining 15% will be distributed evenly in a community. Some places will have high vaccination rates and others will not, either because of differences in access to vaccines or interest in obtaining them.

This is already true in San Diego County, with lower vaccination rates in East County than elsewhere in the region. This is also true around the world, with many countries having only vaccinated a small percentage of their citizens, allowing the virus to spread widely without control in places like India.

Uneven vaccine rollout could eventually make coronavirus outbreaks look a bit like measles outbreaks, Smith said. A single person with the measles virus can infect 12 or more people, but the spread of the virus is mostly contained by high vaccination rates. However, there are still outbreaks in communities with low vaccination rates, such as Marin County, the Orthodox Jewish community in New York and the Philippines. Sometimes these outbreaks spill over into the wider community.

Smith and Martin say it’s unlikely we’ll ever eradicate the coronavirus – not anytime soon, at least. There is only one virus that scientists have eliminated with a vaccine: smallpox. The World Health Organization began this effort in 1959, declaring the disease eradicated in 1980.

Here is the good news: eradication is not necessary. The key is to vaccinate more people as we get back to normalcy. So far, scientists have yet to find a viral variant that no vaccine works against. Keeping a high percentage of people vaccinated, which limits the chances of the virus mutating, will help keep things that way.

“We don’t need to have the goal of eradication to be able to get back to a point as a society where we can live alongside this virus and live our daily lives with minimal disruption,” said said Martin. “You just want to be able to live by his side so that it doesn’t lead to serious illness.”

UT staff editor Paul Sisson contributed reporting.


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