In this issue, “Vaccine-palooza” we are going to cover all the vaccines that have been recommended this Fall and the rationale for each. This season we will have a new RSV vaccine as well as reformulated seasonal Influenza and a COVID booster. With so many, planning is necessary!
Doses of the 2023/2024 seasonal flu shot have already begun to ship and typically vaccination efforts begin in late August or early September each year. Influenza has a seasonal pattern with outbreaks occurring in the winter months primarily (in tropical regions, it may be more year round). But this is why vaccination efforts begin in the Fall, in preparation for such. This season’s vaccine will have either three components (trivalent) or four (quadrivalent) with the latter being recommended for those over the age of 65 or with chronic conditions.
The decision on which strains to include in the vaccine formulation is based on global
surveillance data but, in the end, is a prediction and not always correct. As such, the
effectiveness of the seasonal flu shot can vary from year to year. It is important to note that even if the vaccine doesn’t completely prevent the flu, it can still reduce the severity and complications of the illness should one become infected.
One of my favorite online resources for influenza is Columbia University’s Flu Forecasting System (link: https://cpid.iri.columbia.edu/) which provides geographic spread predictions by US city. Influenza travels east to west so we will see case spikes along the eastern seaboard before we have a surge of cases in Los Angeles. But, for those who travel for business or leisure, this web resource is helpful to see if you are heading into an area with either a high current case load or a predicted increase. Historically, the peak of influenza cases in Los Angeles has occurred in the last week of December and first week of January, coinciding with holiday travel. My general recommendation is that patients have the flu vaccine by Halloween, although those
who have travel to the east coast or Europe may want to have it sooner.
Last year at this time, the FDA authorized the use of Moderna and Pfizer Bivalent Vaccines for a single additional booster dose at the end of August 2022. This updated booster was to be given at least 2 months after completion of a primary series or the most recent booster dose of a monovalent (original) COVID-19 vaccine.
Population uptake of the bivalent booster was abysmal – only 17% of the total US population received a booster dose. That percentage is a bit better for those over the age of 65 years at
Similar to influenza, COVID historically (until 2023 that is) has had a Winter surge although there has been historically a mid-summer increase in cases as well (Figure below).
Smoothed Daily Incidence Case Rate (Per 100,000 population) of SARS-CoV2: Los Angeles Country, California for 2020 (Blue), 2021 (Red), 2022(Yellow), and 2023(Green)
Both the CDC and vaccine manufacturers have indicated that COVID booster shots will move closer to an influenza like pattern with the goal to ‘keep up’ with COVID variants. But this isn’t really a true or fair parallel because the seasonal influenza shot is planned and predicted whereas the COVID booster is reactionary. For instance, the Fall 2023 COVID booster, which should gain FDA approval this month, targets XBB.1.5 a coronavirus subvariant that emerged in late 2022. Unfortunately, XBB.1.5 is no longer the primary circulating variant in the US. In fact, it isn’t the second most common, nor the third. It’s the fourth at 12.3% (link:https://covid.cdc.gov/covid-data-tracker/#variant-summary).
While the expectation is that the updated booster will provide protection against subsequent variants, I think this is going to be a difficult gap to bridge for the US public and uptake will again be low. The CDC would be better served by making a strong case for those over the age of 65 or those with chronic medical conditions to have the shot rather than an across the boards recommendation for everybody to have it.
Most likely, I will advise patients over 65 and those in higher risk groups to strongly consider having the booster by the end of October in time for an expected late November to January surge in cases (although this never fully materialized in 2022 -2023). I have not seen compelling data to support its use in those that are younger and without risk factors for developing severe disease.
While you can have both the flu vaccine and COVID booster at the same time, it may be more
prudent to separate the two. That way in the case of an unlikely, but possible, vaccine reaction -the cause will be apparent.
This Fall will be the first time that an RSV (Respiratory Syncytial Virus) vaccine becomes available. Approved earlier this year, this vaccine has been recommended for adults 60 years and older based on clinical trial data showing that one dose of the vaccine was ‘moderately effective’ in preventing respiratory tract disease from RSV.
Epidemiologically, RSV affects children more severely than adults and also displays a seasonal pattern with outbreaks more common during the winter months. Infection in healthy adults typically results in mild cold-like symptoms but can lead to more severe respiratory infections inhigher risk groups (infants, young children, older adults and those with a weakened immune system).
Developing a vaccine has been complicated due to the complexity of the virus, the fact that prior infection does not protect against re-infection (even amongst those with high specific antibody titers), and the potential for vaccine-enhanced disease in certain populations. Vaccine-enhanced disease occurs when vaccinated individuals experience more severe symptoms upon subsequent exposure to the virus.
The current RSV vaccine is recommended only as a single dose for individuals 60 years and older. Those most likely to benefit would be those with pulmonary disease (such as COPD or asthma), cardiovascular disease, moderate to severe immune compromise, and diabetes. The CDC does not recommend against co-administration with seasonal flu shot or other vaccines although antibody titers for both influenza and RSV were lower when given together. So my recommendation would be to separate RSV vaccination out from other shots by two weeks
The Fall of 2023 is shaping up to be a busy vaccination season with seasonal flu, the COVID booster and the new RSV vaccination. While the flu shot itself is generally well tolerated without significant side effects, my general recommendation would be to separate out the vaccine shots by about 2 weeks – particularly the RSV which is a completely new vaccine and has not been studied widely. The finding that antibody titers of both flu and RSV are lower when given together is yet another reason to separate them out.
Also – if you can’t remember what you’ve had when – we have good news for you! Our office recently has integrated the California Immunization Registry (CAIR, now version 2.0) directly into our Electronic Medical Record. Not only do we send vaccination data to the registry for those receiving shots in the office, we are able to query the state registry for vaccines our patients may have had previously at an outside location.
Recently, the Los Angeles County Health Department reported a “concerning increase” in reported COVID-19 cases, detailing a 32% rise in cases week over week. This is a very curious assertion given that the data published by the County do not show this rise. Week over week data are below:
Smoothed Daily Incidence Case Rate (Per 100,000 population) of SARS-CoV2: Los Angeles Country, California
Cases have been in a very narrow band of 2.2 to 2.6 new daily cases per 100,000 population since mid May. The largest week over week rise has been 16% when going from 2.2 to 2.4. Most recently we have seen a slow rise in the last three weeks of 2.2 to 2.4 to 2.6 but nowhere is there a 32% increase.
Cases have also been steady within our own practice with only 4 to 7 cases monthly since March of this year. So case rates remain at historic lows.
Total COVID-19 Cases and Repeat Infections by Month in 2022/2023: Santa Monica Primary Care
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