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Israeli Study Shows How COVID-19 Immunity Wanes over Time

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An elderly man getting a vaccine by a doctor
Credit: bbernard/Shutterstock

The winter holidays are approaching, and among the many things to be grateful for this year is that nearly 200 million Americans are fully vaccinated for COVID-19. That will make it safer to spend time with friends and family, though everyone should remain vigilant just to be on the safe side. Though relatively uncommon, breakthrough infections are possible. That’s why the Centers for Disease Control and Prevention (CDC) recommends booster shots for several at-risk groups, including folks 65 years and older, those with underlying medical conditions, and people whose occupations place them at high risk of exposure.

One of the main studies providing the evidence for CDC’s recommendation was recently published in the New England Journal of Medicine [1]. It found that vaccine-induced immunity, while still quite protective against infection and severe illness from COVID-19, can wane after several months.

The study is yet another highly informative report from Israel, where public health officials launched a particularly vigorous national vaccination campaign in December 2020. More than half of adult Israelis received two doses of the Pfizer vaccine within the first three months of the campaign. By May 2021, Israel had extremely small numbers of confirmed COVID-19 cases—just a few dozen per day.

But the numbers crept back up in June 2021. The rise also included a substantial number of breakthrough infections in vaccinated individuals. The vast majority of those cases in June—98 percent—were caused by the emerging Delta variant.

Researchers led by Yair Goldberg, Technion-Israel Institute of Technology, Haifa, wondered whether this resurgence of COVID-19 could be fully explained by the rise of the more infectious Delta variant. Or, they wondered, did the waning of immunity over time also play a role?

To find out, the researchers looked to over 4.7 million fully vaccinated Israeli adults, more than 13,000 of whom had breakthrough infections from July 11 to 31, 2021 with SARS-CoV-2. The researchers looked for an association between the rate of confirmed infections and the time that had passed since vaccination. Without any significant waning of immunity, one shouldn’t see any difference in infection rates among people who were fully vaccinated at the earliest opportunity versus those vaccinated later.

The results were clear: the rate of confirmed COVID-19 infection revealed a slow but steady waning of immunity over time. Among individuals 60 years or older who were fully vaccinated last January, the number of confirmed breakthrough infections was 3.3 per 1,000 people during the three weeks of the study. Those who were vaccinated in February and March had lower infection rates of 2.2 per 1,000 and 1.7 per 1,000, respectively. The data revealed a similar pattern in those aged 40 to 59 and those aged 16 to 39.

An important question is whether these breakthrough infections were serious enough to require hospitalization. While such cases were much less common, more than 400 of those with confirmed COVID-19 breakthroughs went on to develop severe illness. And, again, the data show a similar pattern of waning immunity. The rate of severe COVID-19 among adults 60 years of age or older who were fully vaccinated in January was 0.34 cases per 1,000 persons. The rate of severe illness dropped to 0.26 cases per 1,000 among those vaccinated in February and 0.15 cases per 1,000 for those vaccinated in March. The researchers report that the number of severe COVID-19 cases among the younger fully vaccinated groups were too small to draw any conclusions.

While the Delta variant surely has played a role in the resurgence of COVID-19 in recent months, these findings suggest that waning immunity also is an important factor. Understanding these dynamics is essential for making critical policy decisions. In fact, these data were a key factor in the decision by the Israeli Ministry of Health in July 2021 to approve administration of COVID-19 booster shots for individuals who’d been vaccinated at least 5 months before.

Back in the U.S., if you were among those who got your vaccine on the early side—good for you. If it’s been more than six months since your original shots, and if you are in one of the risk groups, you should consider a COVID-19 booster shot to remain optimally protected in the months ahead. I’ll be getting my Moderna booster this week. While you’re at it, consider getting your annual flu shot taken care of, too. The CDC guidelines state that it’s perfectly OK to get your COVID-19 and flu shots at the same time.

Reference:

[1] Waning immunity after the BNT162b2 vaccine in Israel. Goldberg Y, Mandel M, Bar-On YM, Bodenheimer O, Freedman L, Haas EJ, Milo R, Alroy-Preis S, Ash N, Huppert A. N Engl J Med. 2021 Oct 27.

Links:

COVID-19 Research (NIH)

COVID-19 Vaccine Booster Shots (Centers for Disease Control and Prevention)

Frequently Asked Influenza (Flu) Questions: 2021-2022 Season (CDC)

24 Comments

  • Steve White says:

    I am not against the vaccines or boosters, but I think the numbers the Director is citing from this study indicate the media and CDC have given out very misleading information. Instead of saying “In Israel, 1 in 300 people who got vaccinated in January have gotten infected” – a number which I think CDC knows will not scare people enough – and indeed, their own experts believed was not scary enough (they may not have had all the data available now but they certainly knew breakthroughs were rare when they advised on boosters) – to really push boosters, we are given horror stories about significantly reduced protection.
    Stories about breakthroughs, which probably get some people running for their boosters, and others saying :Heck with it, what is the point?” Or other rationalizations.

    Maybe they should have said, “breakthrough are so rare, and so unlikely to be severe, that we do not think boosters are really needed for most healthy people” -or something similar to that. Oh, wait …

    Or, how about “while there is extra protection from getting a booster, for those who were already infected, the rate of reinfection is very low in either case” ?

    I am not even going into the extremely low rate of severe illness among children, and the strong possibility they are better off with natural immunity – remember, the human race, and for that matter, all our ancestor mammalian races, presumably, have dealt with viruses from other species for millions of years. Think about this deeply – maybe we’ve evolved so that children strongly tend to not get severely ill, and tend to get lifelong protection, when exposed to novel viruses. Old folks who are no longer breeding – anything can happen to them – just what we see with this thing so far – and maybe giving kids vaccines, which will protect against one variant (the one they were designed to stop) very well, closely related variants less effectively, and other variants maybe not at all, will set them up to be more vulnerable for the coming variants, than kids who caught the first, apparently least virulent, variant, and now have some immunity to every vulnerable part of it.

    • Doug George Dorner says:

      This is great! I am wondering myself if a person who gets Covid again, are the natural antibodies still strong or did they wane over time? I also wonder, why aren’t we using a killed virus vaccine?

    • Diomedes says:

      ~ Immunity will wane over time if the thymus gland is no longer active, especially in old people, whereas it shrinks with time as one gets older.
      ~ In young people, which is when the thymus is still active, the thymus retains this immunity throughout life via memory antibodies, but since the thymus gland in old people is no longer active, then it cannot generate these memory antibodies for the rest of their life.
      ~ Vaccine shots make sure the body generates & retains memory antibodies immunity, both in young & old people
      ~ However in old people the vaccine’s immunity wanes & it needs to be updated periodically, especially with each new variant.
      ~ Effectiveness of the vaccine is based on how multispectral the initial vaccine shot is in it’s efficiency towards variants & mutations.

    • dhogaza says:

      “Instead of saying “In Israel, 1 in 300 people who got vaccinated in January have gotten infected” – a number which I think CDC knows will not scare people enough”

      But the age stratified data shows the percentage of people who get breakthrough cases increases steadily with age, and in those with suppressed immune systems.

      Which is why the CDC first recommended boosters for those with suppressed immune systems (disease, chemo, whatever) and later approved boosters for those over 65 and for those in public-facing jobs (due to the increased likelihood of exposure).

      “Maybe they should have said, “breakthrough are so rare, and so unlikely to be severe, that we do not think boosters are really needed for most healthy people” -or something similar to that. Oh, wait …”

      Oh, wait, that’s exactly what they’ve said.

      “I am not even going into the extremely low rate of severe illness among children, and the strong possibility they are better off with natural immunity – remember, the human race, and for that matter, all our ancestor mammalian races, presumably, have dealt with viruses from other species for millions of years.”

      While the rate of severe illness and death is infrequent in children, they do get infected and they do infect others, and decreasing the rate of transmission is a definite goal of vaccination against covid. While the vaccines don’t provide 100% protection, they do lower the rate of transmission. This is how we eventually get to the point where the disease is endemic rather than epidemic.

      Data on natural immunity shows it, too, wanes over time and evidence is building that the vaccines provided better, not worse, protection.

      As far as co-evolution with viruses go and the fact that our immune systems protect us from death or serious illness from a wide range of common viruses (common cold viruses, both rhinoviruses and coronaviruses), do keep in mind that back when these viruses first arose in humans or crossed over from that they most likely caused a large number of deaths and cases of serve illness. They weren’t documented because the first exposures happened long ago.

      The point behind vaccines to lower the odds of contracting covid or, if you do, becoming hospitalized or dead is that we don’t actually have to follow the painful path of letting evolution play out.

      ” Think about this deeply – maybe we’ve evolved so that children strongly tend to not get severely ill, and tend to get lifelong protection, when exposed to novel viruses.”

      A visit to an old cemetery should be enough to make it clear that this is not true. Just count the percentage of graves that are of children less than12 years old vs. adult graves. It was common for women to bear several children and to only have one or two survive to adulthood, with most of the deaths being due to childhood diseases which due to modern medicine can be vaccinated against and for those who catch them anyway can usually be treated.

      • David R Feller says:

        You are ignoring that the rate of infect you cite is for a twenty day period, which makes your argument faulty.

    • Robert Lanciotti says:

      For an additional reality check. It is correct to state that 1 in 300 fully vaccinated people were PCR positive-no mention if any of these were symptomatic. It is entirely possible that many were asymptomatic. Further, approximately 1 in 13,000 fully vaccinated people developed severe COVID, and no mention is made if any cases were fatal, so I assume no fatalities. That means severe COVID is extremely rare among fully the vaccinated and that death is completely abrogated. This is good news and tells me that vaccine is very effective. This news is certainly not scary enough to support the CDC/NIH narrative that everyone should run to get a booster!

    • Fahmida P. says:

      Nice writing Steve.I really appreciate this.

  • D.L. says:

    Brilliant comment, Steve. Strongly agree! Thanks for posting

  • PM De Grood says:

    The picture above shows an inadequate methode for vaccination with covid-19 vaccine! Vaccination should be intramuscular.

  • D.L. says:

    The m-RNA vaccines were develops for the sake of speed. Apparently it’s much easier to produce them than an inactivated virus vaccine.

  • DIOMEDES A. says:

    ~ Immunity will wane over time if the thymus gland is no longer active, especially in old people, whereas it shrinks with time as one gets older.
    ~ In young people, which is when the thymus is still active, the thymus retains this immunity throughout life via memory antibodies, but since the thymus gland in old people is no longer active, then it cannot generate these memory antibodies for the rest of their life.
    ~ Vaccine shots make sure the body generates & retains memory antibodies immunity, both in young & old people
    ~ However in old people the vaccine’s immunity wanes & it needs to be updated periodically, especially with each new variant.
    ~ Effectiveness of the vaccine is based on how multispectral the initial vaccine shot is in it’s efficiency towards variants & mutations.

    • Joe says:

      In addition to the spleen and lymph nodes, memory B cells are found in the bone marrow, Peyers’ patches, gingiva, mucosal epithelium of tonsils, the lamina propria of the gastro-intestinal tract, and in the circulation (67, 71–76). Diomedes might wanna try again.

  • Dale G. says:

    As to the above comment that:

    “Further, approximately 1 in 13,000 fully vaccinated people developed severe COVID, and no mention is made if any cases were fatal, so I assume no fatalities. That means severe COVID is extremely rare among fully the vaccinated and that death is completely abrogated.”

    Thank you for clarifying that this conclusion is based on an assumption. I would like to draw your attention to the Israeli study referred to (and properly cited) in the above article; the one published in the New England Journal of Medicine in the article entitled, “Waning Immunity after the BNT162b2 Vaccine in Israel” (Oct 27, 2021). Please consider the following quote from that article:

    “However, the number of polymerase-chain-reaction (PCR) tests that were positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started to rise exponentially in June 2021, with a substantial number of infections being reported in vaccinated persons (Figure 1). This rise in community transmission was followed by a concomitant increase in the numbers of severe cases and deaths, in both the vaccinated and unvaccinated populations.”

    We can see from this quote that vaccinations did not eliminate the possibility of a severe case of COVID-19, or a COVID-19 related death. Feel free to take a good look at the full article. You may find the charts informative as well.

  • Zuccheri Gianni says:

    Generally in vaccinations there is a certain duration of antibody immunity, more or less long.
    Learning with regret that the vaccination coverage for the SARS virus lasts a few months (without also considering the variant problem), I place some points on which to reflect.
    The vaccinated person who lives in environments where the Covid19 virus circulates, probably, even at low doses comes into contact with it, thus inducing a spontaneous strengthening of immunity.
    Is it a problem with the antibody production mechanism or lack of perception of the intruder?
    If so, is he not seen as an enemy or is he not seen at all?
    A worrying question: the control mechanism of the immune system responsible for identifying harmful external agents no longer recognizes that this is an enemy, consequently it would not send the command to the contrast response.
    It is as if the virus has obtained a passport that allows his entry as a known and tolerated guest.
    This would happen because with the self-production mechanism of the antigen (given by the vaccine mRNA), in some way it coexists with molecular sensors of some of our immune cells, which get used to tolerating the viral protein.

    Thus a very common phenomenon for many pharmacological substances would arise, that of tachyphylaxis.
    “By introducing certain substances into the organism, even in small quantities but with rather short intervals between the various administrations, these substances lose their properties notably and quickly (effectiveness in particular) in the organism that receives them. Tachyphylaxis has been observed in the human being for various types of substances.
    This is due to the fact that very often the substances introduced into our body are already produced by it, even if in smaller quantities; this causes a negative feedback effect, which on the one hand leads our organism to lose the ability to produce these substances – since they are already found naturally within us and therefore there is no reason to produce them again -, on the other instead it often causes the phenomenon of resistance, that is, our body raises its basal threshold of sensitivity to a substance ”
    Is it the reason why in this case it is necessary to introduce with a higher dose the drug substance in question: in the context of the mRNA vaccine, another dose of this antigen (booster shot)?

    • Zuccheri Gianni says:

      I thank Dr. Collins for illustrating this important issue of immunity related to Covid19.

      Tachyphylaxis versus vaccine mRNA-induced protein?
      I apologize, I would like to explain better where I indicate the problem of antibody decline and the relationship of the antigenic stimulus that we can receive, based on the presence of the SARS-CoV-2 virus in the environment.
      Previously I assumed that the continuous stimuli given by the environmental viral load led to a reinforcement and therefore a prolongation of antibody production in the vaccinated individual, without being infected.

      So why does this unwanted antibody decline occur?
      Is the mechanism of assembly of antibodies altered or lack of perception of the intruder towards which to implement the antibody production ?

      Thinking back to how the antibody production instruction with vaccine mRNA works, the paradoxical hypothesis thus appears: repeated antigenic contact derived from the environment would produce an effect of “indifference”
      All this would be traced back to the pharmacological phenomenon called Tachyphylaxis.

      Which would be amplified by some animals (as reported by various studies) that are theoretically susceptible to SARS-CoV-2: what role do these play in the epidemic trend?

      “Ever since the coronavirus started spreading around the world, scientists have worried that it could leap from people into wild animals. If so, it might lurk in various species, possibly mutate and then resurge in humans even after the pandemic has subsided…”

  • Marie says:

    I am eager to get a booster, but at age 62 (almost 63) and retired, I do not yet qualify per FDA/CDC, even though it has been over 6 months since my vaccination. There are no data that says age 65 is the ‘magic’ cut-off for boosters.

    I live in a state that now has incredible surging of cases, including an apparent 25-30% of cases being breakthrough cases. We are now less than 2 weeks until Thanksgiving. Now it appears I may have to be alone again on Thanksgiving this year. Why do we still have to wait for a booster? There does not seem to be any scientific reason presented why a 62 year old should not be able to get a booster now. I am not in the risk group for myocarditis (young, male), so why do I have to wait?

    I hear that Colorado has opened up boosters for all adults now – even before FDA/CDC determination. Some counties in California and Michigan have also decided to open their boosters up to all adults, rather than wait for FDA/CDC. People are getting very worried – and I think FDA/CDC have missed the boat on this one – since the window of time for people like me to get an effective booster has now closed for Thanksgiving.

    A fall/winter surge was not unexpected, everyone knows the upcoming holidays would pose additional risks, and the knowledge of waning immunity after 6 months has been known for a few months now. To have all of these things converge around the same time – and have our FDA/CDC not take those things into consideration for the booster rollout seems unconscionable and unexplainable to me.

    Even though I am retired and do not work in the CDC ‘high risk’ jobs, I still have to interact in other ways in the community – that can put me at risk. As one example, I have to take my car in for a necessary appointment next week – and wait in a probably crowded indoor waiting room for an extended period of time in a space I cannot control and probably with a lot of people who won’t be wearing masks. But necessary life activities like that do not fit into CDC’s thinking at all . . .

  • Nichole says:

    I am eager to get a booster, but at age 62 (almost 63) and retired, I do not yet qualify per FDA/CDC, even though it has been over 6 months since my vaccination. There are no data that says age 65 is the ‘magic’ cut-off for boosters.

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