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The Success Of Covid-19 Vaccines Should Be Measured By Hospitalization Rates, Not Infection Rates – Forbes

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Dr. Matt Binnicker, an expert in the diagnosis of infectious diseases, explains why hospitalization rates are the key metric against which to measure the success of Covid-19 vaccines.


Although more than 350 million doses of Covid-19 vaccines have been administered in the United States, the SARS-CoV-2 delta variant is racing across the nation, causing an increasing number of infections and hospitalizations. On July 12, 2021, the Centers for Disease Control and Prevention (CDC) reported 22,457 new cases of Covid-19. A month later, that number spiked to 146,949. During the same timeframe, the number of new hospital admissions due to Covid-19 increased from 2,779 on July 12 to 11,493 on August 12.

It is now clear that vaccinated individuals can test positive for Covid-19, although at a significantly lower rate compared to the unvaccinated population. The CDC recently reported an outbreak of Covid-19 in Barnstable County, Massachusetts, in which 74% (346 out of 469) of cases occurred among those who were fully vaccinated. This has raised questions about the efficacy of Covid-19 vaccines and led to social media claims that vaccinated persons are ”super spreaders.“

When Vaccinated Individuals Test Positive for Covid-19, Does That Mean Vaccines Are Ineffective?

For infectious diseases, like Covid-19, there are three key terms to be aware of that influence discussions on vaccine efficacy. The first is exposure, which means coming into contact with the virus. This may occur when someone with Covid-19 coughs nearby, or when an individual touches a door handle or surface that is contaminated with the virus. Vaccines don’t prevent exposures, and it’s likely that many of us have been, or will be, exposed to SARS-CoV-2. The second term is infection, which occurs after an exposure and requires that the virus infects our cells and replicates. Some – but not all – vaccines can prevent infection, yet the current Covid-19 vaccines don’t appear to result in sterilizing immunity (i.e., the ability to prevent infection). In other words, even those who are vaccinated against Covid-19 may be infected with the virus. Importantly, not everyone who is infected with SARS-CoV-2 becomes ill. The third term is disease, which means that the viral infection results in clinical signs or symptoms (e.g., cough, fever, shortness of breath). The Covid-19 vaccines have been shown to be highly effective at preventing disease.

Most Covid-19 tests look for viral RNA, which is copied inside our host cells after an infection occurs. These tests (e.g., PCR) are very sensitive, meaning that they can detect extremely small amounts of the viral RNA, even in persons who don’t develop disease. As the number of vaccinated individuals increases in the country, it is expected that the number of positive tests among the vaccinated population will also increase, especially as testing continues to be performed in the asymptomatic population. Because of this, test positivity rates provide a good indication of viral prevalence (i.e., how much virus is in a community), but are not a reliable measure of vaccine efficacy.

What Should Be Used to Assess Vaccine Efficacy?

Covid-19 vaccines have been shown to be highly effective at preventing symptomatic disease, with the Pfizer and Moderna mRNA vaccines demonstrating >90% protection during clinical trials. As the delta variant has become predominant in the United States, the number of hospitalizations – including among pediatric patients – has skyrocketed in certain parts of the country. However, a common theme is being observed at healthcare centers across the nation – the vast majority of hospitalizations are occurring among the unvaccinated. Vermont, the state with the highest vaccination rate (67%), reported a new daily admission rate of 0.5 per 100,000 population on August 13. In comparison, Alabama, which has the lowest vaccination rate in the country (35%), experienced a new admission rate of 8.65 per 100,000 residents. Among states with at least 50% of residents being fully vaccinated, the average new daily admission rate is 1.3 per 100,000 residents compared to an average rate of 3.9 per 100,000 in states with less than 50% of residents who are vaccinated.

To Avoid Severe Disease and Hospitalization, Get Vaccinated

The true measure of success for current Covid-19 vaccines is the reduction in severe disease and hospitalization among infected individuals. Vaccinated persons can still be infected, and may test positive for Covid-19, but the rate of serious illness requiring hospitalization among the vaccinated population is significantly reduced. However, given the uncertainty of the long-term consequences of Covid-19, it will be important to take measures to prevent infections until most, especially young children, have had the opportunity to be vaccinated. This will require a continued focus on additional mitigation measures, such as masking and physical distancing.

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Chris Rock says he has COVID-19, urges vaccination – San Francisco Chronicle

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Sep. 19, 2021Updated: Sep. 19, 2021 11:45 a.m.

FILE – In this March 30, 2019 file photo, Chris Rock presents the award for outstanding comedy series at the 50th annual NAACP Image Awards at the Dolby Theatre in Los Angeles. Chris Rock on Sunday, Sept. 19, 2021 said he has been diagnosed with COVID-19 and sent a message to anyone still on the fence: “Get vaccinated.” (Photo by Chris Pizzello/Invision/AP, File)Chris Pizzello/Chris Pizzello/Invision/AP

NEW YORK (AP) — Chris Rock on Sunday said he has been diagnosed with COVID-19 and sent a message to anyone still on the fence: “Get vaccinated.”

The 56-year-old comedian wrote on Twitter: “Hey guys I just found out I have COVID, trust me you don’t want this. Get vaccinated.”

Rock has previously said he was vaccinated. Appearing on “The Tonight Show” in May, he called himself “Two-shots Rock” before clarifying that he received the one-shot Johnson & Johnson vaccine.

“You know, I skipped the line. I didn’t care. I used my celebrity, Jimmy,” he told host Jimmy Fallon. “I was like, ‘Step aside, Betty White. Step aside, old people. … I did ‘Pootie Tang.’ Let me on the front of the line.'”

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'Waning immunity?': Experts say term leads to false understanding of COVID-19 vaccines – CHEK

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The idea of waning immunity has picked up steam in recent weeks, with some countries using it to justify rolling out third-dose COVID-19 vaccine boosters to their populations.

But immunologists say the concept has been largely misunderstood.

While antibodies — proteins created after infection or vaccination that help prevent future invasions from the pathogen — do level off over time, experts say that’s supposed to happen.

And it doesn’t mean we’re not protected against COVID-19.

Jennifer Gommerman, an immunologist with the University of Toronto, said the term “waning immunity” has given people a false understanding of how the immune system works.

“Waning has this connotation that something’s wrong and there isn’t,” she said. “It’s very normal for the immune system to mount a response where a ton of antibodies are made and lots of immune cells expand. And for the moment, that kind of takes over.

“But it has to contract, otherwise you wouldn’t have room for subsequent immune responses.”

Antibody levels ramp up in the “primary response” phase after vaccination or infection, “when your immune system is charged up and ready to attack,” said Steven Kerfoot, an associate professor of immunology at Western University.

They then decrease from that “emergency phase,” he added. But the memory of the pathogen and the body’s ability to respond to it remains.

Kerfoot said B-cells, which make the antibodies, and T-cells, which limit the virus’s ability to cause serious damage, continue to work together to stave off severe disease long after a vaccine is administered. While T-cells can’t recognize the virus directly, they determine which cells are infected and kill them off quickly.

Recent studies have suggested the T-cell response is still robust several months following a COVID-19 vaccination.

“You might get a minor infection … (but) all of those cells are still there, which is why we’re still seeing very stable effectiveness when it comes to preventing severe disease,” Kerfoot said.

A pre-print study released this week by Public Health England suggested protection against hospitalization and death remains much higher than protection against infection, even among older adults.

So the concept of waning immunity depends on whether you’re measuring protection against infection or against severe disease, Kerfoot said.

Ontario reported 43 hospitalized breakthrough cases among the fully vaccinated on Friday, compared to 256 unvaccinated hospitalized infections. There were 795 total new cases in the province that day, 582 among those who weren’t fully vaccinated or had an unknown vaccination status.

British Columbia, meanwhile, saw 53 fully vaccinated COVID-19 patients hospitalized over the last two weeks, compared to 318 unvaccinated patients.

“You’ll hear people say that vaccines aren’t designed to protect infection, they’re designed to prevent severe disease,” Kerfoot said. “I wouldn’t say necessarily it’s the vaccine that’s designed to do one or another … that’s just how the immune system works.”

Moderna released real-world data this week suggesting its vaccine was 96 per cent effective at preventing hospitalization, even amidst the more transmissible Delta variant, and 87 per cent effective at preventing infection — down from the 94 per cent efficacy seen in the clinical trials last year.

Moderna CEO Stephane Bancel said that dip “illustrates the impact of waning immunity and supports the need for a booster to maintain high levels of protection.”

Pfizer-BioNTech has argued the same with its own data, and an advisory panel to the U.S.-based Food and Drug Administration voted Friday to endorse third doses for those aged 65 and older, or at high risk for severe disease.

However, the panel rejected boosters for the general population, saying the pharmaceutical company had provided little safety data on extra jabs.

Gommerman said the efficacy data presented by Moderna doesn’t signal the need for a third dose.

“The fact it protects 87 per cent against infection, that’s incredible,” she said. “Most vaccines can’t achieve that.”

Bancel said Moderna’s research, which has yet to be peer reviewed, suggested a booster dose could also extend the duration of the immune response by reupping neutralizing antibody levels.

But Dr. Sumon Chakrabarti, an infectious physician in Mississauga, Ont., said looking solely at the antibody response is misleading, and could be falsely used as justification for an infinite number of boosters.

Israel, which has opened third doses for its citizens, recently talked about administering fourth doses in the near future.

“This idea of waning immunity is being exploited and it’s really concerning to see,” Chakrabarti said. “There’s this idea that antibodies mean immunity, and that’s true … but the background level of immunity, the durable T-cell stuff, hasn’t been stressed enough.”

While some experts maintain boosters for the general population are premature, they agree some individuals would benefit from a third jab.

The National Advisory Committee on Immunization has recommended boosters for the immunocompromised, who don’t mount a robust immune response from a two-dose series.

Other experts have argued residents of long-term care, who were prioritized when the rollout began last December, may also soon need a third dose. The English study suggests immunity could be waning in older groups but not much — if at all — among those under age 65.

Chakrabarti said a decrease in protection among older populations could be due more to “overlapping factors,” including their generally weaker immune systems and congregate-living situations for those in long-term care.

“These are people at the highest risk of hospitalization,” he said. “Could (the length of time that’s passed following their doses) be playing a role? Yeah, maybe.”

While we still don’t know the duration of the immune response to COVID-19 vaccination, Gommerman said immune cells typically continue to live within bone marrow and make small amounts of antibodies for “decades.”

“And they can be quickly mobilized if they encounter a pathogen,” she said.

Melissa Couto Zuber/The Canadian Press

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Chris Rock gets COVID, urges vaccine – South Coast Register

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