Opinion: Covid-19 vaccine effectiveness declines rapidly; seniors need to keep up their immunity, and we need a better vaccine

By Kevin Kavanagh for Infection Control Today

I am at high risk for severe Covid-19, being 65 years or older, with additional health problems. I received my bivalent booster as soon as possible and am approaching my 6-month anniversary. I, thus, watched the CDC’s last Advisory Committee on Immunization Practices meeting with great interest regarding their recommendations for when to obtain my next booster.

Reuters reported that the committee concluded, “There is not sufficient evidence to recommend more than 1 Covid-19 booster shot a year for older people and those with weakened immune systems,” but the committee did voice some flexibility. It needs to be stressed that there was an absence or lack of data—rather than a presence of data—indicating the durability of vaccine immunity, justifying annual boosters.

There was no vote regarding the timing of booster doses, but there was nowhere near a unanimous consensus. Michael Hogue of the American Pharmacists Association said, “We want those clinicians to be able to make good decisions for the individual patient based upon their comfort and desire as long as we have safety in mind, and it is clear that we do have a very safe vaccine with our bivalent vaccine. So, I feel that flexibility needs to be put into this some way, with both older adults and people with immunocompromising conditions.”

I did not hear calls for approving a more frequent administration schedule. One committee member said those over 65 should be allowed to discuss off-label use with their physician in order to receive the booster sooner. Almost all the discussion centered on messenger-RNA vaccines, with little mention of Novavax or the urgent need for newer, more durable vaccines.

Vaccine effectiveness is an important point. Although much of the younger population received a get-out-of-hospital free card for the latest variant, senior citizens were in its crosshairs. Since May 2022, those over 75 had a higher rate of hospitalization than in the Delta surge; those 65 to 75 had about the same. Both age groups continue to be at high risk for death and disability.

However, when I saw data on effectiveness of the monovalent vaccines, the two-dose-or-more immunization that preceded the bivalent vaccine, I felt foreboding. The data showed that for those 65 years and older, the effectiveness of two or more monovalent doses at preventing hospitalizations fell to 28% in less than a year.

Among younger people, the monovalent vaccines were only 19% effective. This finding may seem paradoxical, but could be explained by the elderly leading a safer lifestyle and the possibility that immunity produced by previous infections may not have been as durable. Neither explanation bodes well for vaccine effectiveness lasting a year.

For the bivalent booster, effectiveness against hospitalization fell rapidly, from 52% at a median of 32 days to 31% at a median of 74 days (67-85 days) after the last dose. It should be noted that this effectiveness is on top of some residual immunity from the monovalent vaccine, since the monovalent vaccine was used as the reference.

Let’s face it. The results are dismal, with little durability from an immunity boost from a bivalent booster after an individual has had a monovalent vaccine. The benefit from the bivalent booster rapidly diminishes, and its efficacy in preventing hospitalizations two months after receiving the booster is poor and would be expected to be poorer in the elderly.

Is the bivalent booster worth taking? Yes, definitely. However, this differs from the booster or vaccine we need to navigate this pandemic. We need another warp-speed initiative for vaccine development—a vaccine that is more durable and can reduce spread. The risk of continuing to use a vaccine with reduced effectiveness is shown when the vaccine was seemingly less effective in the young. When vaccinated, many view themselves as invincible and can increase risky behavior far beyond the vaccine’s benefits.

It is critical for the elderly to keep their immunity as high as possible. Monoclonal antibodies are no longer effective with the new variants, and far too many cannot receive Paxlovid because of drug interactions. Molnupiravir is often not prescribed since it works by creating viral mutations and has been implicated in speeding variant evolution.

At the conclusion of the CDC committee meeting, my primary impression was that we senior citizens might be viewed as expendable. Far too few policymakers are concerned about our well-being and willing to make the hard decisions that must be made to assure our safety during this pandemic. After looking at the data, I will consult my physician about receiving a booster on an accelerated schedule, possibly at six months.

Kevin Kavanagh is a retired physician from Somerset and chairman of Health Watch USA. This is an edited version of his original article, which was first published in Infection Control Today.

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