August 18, 2021
Guest Post: Dr. Ted Li, MD
REPRINTED WITH PERMISSION
I thought in June that there’d be no further need for emails about covid-19. But the Delta variant has changed all that. I’m reminded of anti-submarine warfare in WW II whereby a protective measure appears to work, but then the submarines come back with new tricks. Unfortunately, a third of the convoy won’t turn out their lights at night (infringes on their freedom) and many ships won’t deploy depth charges (shock waves might stress the propellors or hasten hull rust). I write now regarding what we know about getting our ships safely to port.
Vaccine Protection: How Good is it?
The vaccines, especially the mRNAs (Moderna, Pfizer) were highly effective at preventing both infection and serious illness/death against the original covid-19 virus. With the Delta variant, these vaccines still protect well against serious illness/death, but not so well against infection and the ability to spread the virus.
NOTE: Since July 4, seven of my fully vaccinated patients have contracted covid. None have required hospitalization, but one person felt at least moderately ill, and another (see below regarding J & J vaccine) had suboptimal antibody levels and received a monoclonal antibody infusion.
Meanwhile, people with depressed immunity due to hematologic disorders or medications (chemotherapy, biologic agents for autoimmune disease, corticosteroids, immune suppressants for organ transplants) have not reliably achieved immunity after two doses. Such people were not included in the initial vaccine trials. Last week, the FDA authorized a third dose for this sub-group.
NOTE: Immunosuppressed does NOT mean being above a certain age or having multiple medical problems or stress/fatigue lowering one’s immunity. The FDA is referring to people with specific conditions or taking certain medications.
If you fall into this category, you should get a booster dose now.
Vaccine Protection: How They Differ
Both Pfizer and Moderna use mRNA that primarily enters your muscles to temporarily instruct the cells to make covid spike protein. This prepares your immune system to disable the part of the virus that docks with your cells.
Moderna: This is the most potent of the vaccines. One Moderna injection contains roughly triple the mRNA content of the Pfizer vaccine. This is likely why the Moderna (2nd dose in particular) vaccine is associated with more fever, aches, and swelling. Because of its higher potency, I recommend Moderna for people with immunodeficiencies.
Pfizer: Despite a lesser amount of mRNA, the Pfizer vaccine still achieves high levels of antibodies. The levels may not be quite as high, but side effects are less. While Pfizer protection from serious illness still looks good overall, there are concerning data from Israel. Having mostly deployed Pfizer vaccines, Israel is reporting hospitalizations among fully vaccinated people - primarily older patients with co-morbidities (hypertension, heart disease, diabetes). Similarly, Iceland is currently experiencing a surge of infections in a highly vaccinated (mostly Pfizer) population, but with little serious illness and no deaths since May.
Johnson & Johnson: This is a DNA vaccine. The DNA enters your cells, gets translated into mRNA which then makes spike protein. Unlike mRNA vaccines that are enveloped within a lipid membrane, J & J uses a disabled adenovirus as a delivery vehicle. Adenoviruses are a common cause of respiratory infection. The antibody levels achieved have been less consistent, especially among people over age 50. This may be due to immunity acquired from having had prior adenovirus infections; the vaccine-containing adenovirus shell gets swatted away before it can deliver its message. While some people get excellent levels, we’ve encountered others who either developed no antibodies or only low levels.
Natural Immunity: Natural is not better. Think of the virus as a circus car filled with clowns (infectious RNA). The key is to disable the door handles. The vaccines instruct the immune system to target door handles (spike protein) exclusively and abundantly. Even if the door handles mutate, the abundance of antibodies still serves to largely contain the clowns. With natural immunity, the immune system makes a hodgepodge of antibodies. Some might target the bumper or the tires. These would not be protective (a.k.a. neutralizing). The amount of anti-spike protein antibody following infection appears to vary. In Denmark, prior to Delta, the protection acquired by prior infection was about 80% during their second surge. This would be comparable to the J & J vaccine.
Vaccine Protection: For How Long?
All immunity, unless re-challenged, declines over time. I don’t see the protection somehow disappearing at some fixed time; the process is gradual and varies by individual. According to an unpublished report of Pfizer trial volunteers (immunized during the spring of 2020), vaccine efficacy against symptomatic disease remained high over six months but slightly decreased from 96 percent up to two months, to 90 percent between two and four months, to 84 percent from four to six months.
What has become clear is that a 3rd dose greatly elevates antibody levels. It can increase them 5-10 times higher than the peak after two doses. Moreover, the duration of the protection is likely to last longer. Because a 3rd dose confers much greater and longer protection, the Administration announced today that booster shots will be offered beginning September 20 to everyone age 12 and up– eight months following completion of the initial vaccine series.
The Bottom line:
Infections and transmission are occurring among vaccinated people, but with little serious illness. But more serious illnesses may accrue over time as vaccine protection wanes.
Moderna and Pfizer vaccines are essentially the same vaccine, except Moderna is three times stronger. In hindsight, perhaps (à la Goldilocks) an in-between dose would have been just right.
Both J & J vaccine and immunity from covid infection confer less predictable protection. I suggest that people over 50 who received J & J check their antibody levels. If low, I would switch to an mRNA vaccine rather than repeat the J & J.
Immunocompromised people need a third dose to achieve adequate protection. The FDA has already authorized boosters for people with bona fide immunodeficiencies.
Protective antibodies gradually drift down. A 3rd (booster) dose after six months further elevates antibody levels by a factor of five or more; the duration is likely greatly prolonged. But if you had significant side effects, especially with Moderna, I would take a lower dose of Moderna or switch to Pfizer. As of September 20, vaccine boosters will be offered to everyone above age 12 – starting eight months after their initial vaccinations.
Dr. Ted Li has been in private practice in Washington, DC since 1989. In 2010 he transitioned to a personalized care model, offering many unique benefits.
I don’t believe the data on antibody levels after 3rd dose of mRNA has been peer-review published. But these conclusions come from three sources:
- I’ve checked antibody levels among my patients with immunodeficiencies or taking immunosuppressants. Not surprisingly, some had suboptimal antibody levels after two doses. When these people were given a third dose, the antibody levels rose dramatically – in some cases more than 15-fold. (Note, none of my patients are organ-transplant recipients; they are in a separate category. But even there, some organ transplant recipients have responded to a third dose – https://jamanetwork.com/journals/jama/fullarticle/2782538
- My contacts at NIH corroborate this observation about levels rising sharply with a third dose.
- Pfizer has submitted data about antibody levels after a 3rd dose to FDA: https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-submission-initial-data-us-fda
- Data slide from White House 8/18/21. The transcript of the conference – https://www.whitehouse.gov/briefing-room/press-briefings/2021/08/18/press-briefing-by-white-house-covid-19-response-team-and-public-health-officials-50/