What is herd immunity? Why is it so important to us with CLL and how many people need to be vaccinated to protect a community?

[AussieNeil]

The term herd immunity comes from the observation of how a herd of buffalo forms a circle, with the strong on the outside protecting the weaker and more vulnerable on the inside.

This is similar to how herd immunity works in preventing the spread of infectious diseases. Those who are strong enough to get vaccinated directly protect themselves from infection. They also indirectly shield vulnerable people who cannot be vaccinated. (That's us - Neil)

There are various reasons a person may not be able to be successfully vaccinated. People undergoing cancer treatment, and whose immune systems are compromised, for instance, are impaired in their ability to develop protective immunity from all vaccines. Often, people who can’t be vaccinated are susceptible to the most serious consequences from being infected.

That last paragraph applies to us. We can't be vaccinated with live vaccines, because with our compromised immune systems, we can become ill from live vaccines, despite them being weakened (attenuated) so that risk is not a concern for healthy people. When we are being treated for our CLL, vaccinations are less effective, because CLL treatments wipe out good B-cells as well as CLL cells. We need good B-cells to respond to the vaccine and produce antibodies (IgA, IgG, IgM) to protect us from the infectious disease.

For a contagious disease to spread, an infectious agent needs to find susceptible (non-immune) people to infect. If it can’t, the chain of infection is interrupted and the amount of disease in the population reduces.

Another way of thinking about it is that the disease needs susceptible victims to survive in the population. Without these, it effectively starves and dies out.

This article excellently illustrates how herd/community immunity works and explains how vaccine coverage needed to protect a community varies by disease type. As can be seen in the included table, measles and pertussis (whooping cough) are extremely infectious and require over 92% vaccination coverage to achieve herd immunity. The recent measles outbreaks are because vaccination levels in some communities have dropped lower than this threshold. Twenty years ago, measles was declared eliminated in the USA due to a vaccination program that prevented an average of 6,000 deaths per year, based on the reported death rate from 100 years ago : cdc.gov/measles/about/histo...

The overwhelming success of measles vaccinations means many people have no memory of what this disease looks like, and this has resulted in its effects being underestimated. Measles can cause blindness and acute encephalitis (inflammation of the brain), which can result in permanent brain damage.

Herd immunity, or community immunity, as it’s sometimes called, is a powerful public health tool. By ensuring those who can be vaccinated do get vaccinated we can achieve herd immunity and prevent the illness and suffering that comes from the spread of infectious diseases.

Full article by Hassan Vally, Associate Professor, La Trobe University, Australia: theconversation.com/what-is...

Vaccinations - for flu, pneumonia and other things

healthunlocked.com/cllsuppo...

Neil

This is an unlocked post: healthunlocked.com/cllsuppo...

[MsLockYourPosts Passed Volunteer]

I always come up with "herd mentality" when describing this. Drove Chris Dwyer nuts, but either term really does work.

[81ue]

Now that I'm in neutropenia I've been afraid to get vaccinated even though it's the non-live shingrix vaccine that I wanted. I have an appointment this week and planned to ask if I should wait for higher neutrophils? Anyone get an answer to this from their own doctor? I went on the shingrix wait list and they called me just after the test that showed too low neutrophils so I wasn't comfortable with proceeding with the shot. Probably lost my place on the wait list

[MsLockYourPosts Passed Volunteer in reply to 81ue]

AussieNeil has commented on the issue of vaccines when dealing with a more compromised immune system. I'm sure that he can give you some good information tomorrow (UK time).

[AussieNeil Partner Administrator in reply to MsLockYourPosts]

I know from personal experience that you are required to have a neutrophil count of over 0.5 (normal range 1.8 to 8 or thereabouts) before having a flu vaccination. I couldn't find any information about requiring a suitably safe neutrophil count prior to Shingrix vaccinations, but given the risk of your body overreacting and possibility triggering febrile neutropenia, I consider it would be prudent to do the same before any vaccination. Ask your doctor or specialist.

Neil

[HopeME in reply to 81ue]

Hi 81ue:

I had 6-rounds of BR treatment which concluded in Oct 2018. After treatment I switched to a CLL specialist and asked him about getting the Shingrex vaccination. He recommended I wait because he didn’t feel the immunization would be very effective immediately after my treatment. He prescribed Acyclovir at that time and said it is highly effective in preventing shingles. I plan to ask him about Shingrex again in the fall.

Best

Mark

[81ue in reply to HopeME]

Thank you Mark. That reminds me that I was given famcyclovir and instructed to take that if there was a virus but haven't yet had a problem that required me to use it

[Myrddin]

The lack of herd immunity following so many not getting vaccinated is a risk to us and our children and grandchildren as is seen in the increase in deaths from conditions that we had almost forgotten all because of some fake results that are still doing the rounds.

[markjeep51]

The last time I heard of this topic was in 1972. I was in the military for a short period of time but was discharged during basic training due to a medical injury. But very shortly after I left the military, I got sick; headaches, dizziness, could not concentrate. I remember going to a doctor after I was discharged and was told that I had a virsus and the only way I was going to get better was to stay with that small group of soldiers and breath in their ( the groups) antibodies. I was in college at the time immediately after I left the military. It was very difficult to concentrate and study due to my illness. But eventually after several years, I apparently got better.

[81ue in reply to markjeep51]

Breathing in antibodies is an interesting concept, but I tried internet search and nothing comes up. I tried 'air antibodies' and 'aerosolized antibodies' etc. If people with disease can aerosolize their germs/viruses when they cough and sneeze and infect others then it would be great if healthy people could aerosolize their virus antibodies and give it to others. I just can't find anything to read that would support that idea.

[markjeep51 in reply to 81ue]

I agree and have not read anything on aerosolized antibodies. But as I remember, it was a common statement made, back in the 70s, to people who served with the US Marines. But I have not seen scientific basis for such a statement.

[AussieNeil Partner Administrator]

Just received today from The Conversation, "a special newsletter outlining the evidence for the safety and efficacy of vaccines from around the globe, and how we can go about advocating for vaccines – which have saved more lives than any other medical intervention in history."

theconversation.createsend....

Note the quote from Gregory C. Mason, Associate Professor of Economics, University of Manitoba - “Social media has created echo chambers of misinformation and it is easy to fall into a circle of ‘virtual’ authorities that first create then build on misinformation.”

[PaulaS Volunteer in reply to AussieNeil]

Thanks for this, Neil. A good article - well worth reading.

Paula

[AussieNeil Partner Administrator]

More compelling evidence that vaccination against measles is better than having the disease, from a Podcast commentary transcript by Rick Lange, MD, Texas Tech; Elizabeth Tracey, Johns Hopkins Medicine on a Netherlands study of 77 unvaccinated children before and two months after natural measles virus infection (with my emphasis).

Elizabeth: ...This was in the journal Science and also in Science Immunology. There are two papers relative to this. Just as a review, the paper highlights the fact that there are over 100,000 deaths annually from measles worldwide...

:

Rick: When someone gets a measles infection, they have lifelong immunity to measles. However, about 10% to 15% of those individuals have prolonged immunosuppression, even up to five years after they had the measles. They call it "immune amnesia." Now, by the way, it doesn't occur in kids that are vaccinated. They don't develop the immune suppression. It's only in those that develop the active infection.

Elizabeth: Again, I know we both agree that this is very compelling evidence that vaccination is just so, so important.

medpagetoday.com/infectious...

Neil

[sllincolorado]

Just pinged my doc this morning about being around people with active shingles (dear friend in much pain). I have had both shingrix shots and had chickenpox as an infant (you can't catch shingles but you can catch chickenpox from shingles).

"not a great idea...to be exposed to someone with active shingles. acalabrutinib is an immunosuppressive treatment and it is not 100% that her prior history of chickenpox or the shingrix vaccine would be fully protective."

Since I feel pretty good I must admit that until recently I have not been concerned about exposure - but last week received flu and 1st pneumonia shot. And even though I often think about a new job, I should be grateful I work from home so I do not have much exposure to whatever cold/flu/illness is making the rounds.

[AussieNeil Partner Administrator]

Discouraging news on community acceptance of vaccinations, when the world awaits access to SARS-CoV-2 vaccinations so we can return to 'normal'. With my emphasis:

"Globally, more than 207,000 people died from measles in 2019 as the number of cases of the highly contagious but preventable disease reached a 23-year high, researchers from WHO and the CDC reported.

:

COVID-19 is complicating global efforts against measles by making it harder to vaccinate children and conduct proper surveillance, Patel and colleagues said.

:

According to the report, there were 869,770 cases of measles reported globally in 2019 — a 556% increase since 2016, when the world reported historic lows in both deaths and cases from measles. It was the highest total since 1996.

The estimated 207,500 deaths from measles in 2019 represented a nearly 50% increase from 2016 and an increase of close to 70,000 deaths over the 2018 total.

:

“In all WHO regions, the fundamental cause of the resurgence was a failure to vaccinate, both in recent and past years, causing immunity gaps in both younger and some older age groups,” Patel and colleagues wrote.

healio.com/news/infectious-...

Neil

[AussieNeil Partner Administrator]

Fascinating BBC article about measles resetting the immune system. bbc.com/future/article/2021...

"Enter "immune amnesia", a mysterious phenomenon that's been with us for millennia, though it was only discovered in 2012. Essentially, when you're infected with measles, your immune system abruptly forgets every pathogen it's ever encountered before – every cold, every bout of flu, every exposure to bacteria or viruses in the environment, every vaccination. The loss is near-total and permanent. Once the measles infection is over, current evidence suggests that your body has to re-learn what's good and what's bad almost from scratch."

From a 2019 NIH Director's Blog, Dr Francis Collins on measles induced immune amnesia

directorsblog.nih.gov/tag/i...

Neil