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  • Writer's pictureWilliam Miller, MD

Booster Shot for Moderna, J&J Considered

Booster shots for COVID vaccines are again in the news. This time for Moderna and Johnson & Johnson (J&J). Both companies provided the FDA this week with research reports that show booster shots enhance effectiveness and remain safe. In late September, the FDA approved a booster shot for the Pfizer vaccine for selected persons who are at highest risk. If the FDA approves these vaccines, it will likely be for the same selected groups which include over age 64, or at high risk for serious COVID do to other illnesses, or who have occupational risk such as front-line health care workers. One must also be out more than six months from completing the initial vaccination.

As a reminder from previous Miller Reports that have dealt with the vaccines, waning effectiveness has been expected as immunity to coronaviruses in general, such as those that cause the common cold, are not sustained from year to year. Thus, a vaccine which works by imitating a coronavirus infection would not be expected to carry over either.

The Pfizer vaccine was approved for a booster because data showed that its effectiveness was waning somewhat faster than the Moderna. At 6 months it is still effective in reducing the risk of hospitalization, serious illness and death at about 77%, but not as much as in the first 3 months when it is 94% effective. The Moderna vaccine appears to hold on at about 90% effective at 6 months raising the valid question of is it even necessary to get a booster shot since that is only slightly less than the initial effectiveness of 92%. These results were published in the CDCs Weekly Morbidity and Mortality Report (MMWR) for September 24th. The definition in the report of “vaccination effectiveness” was preventing hospitalization if COVID infection occurs in someone who is vaccinated.

Pfizer and Moderna use similar technology to induce a response from our immune system, triggering the production of antibodies against the virus that causes COVID. However, the Pfizer shot contains only 30 micrograms of the vaccine material while the Moderna has 100 micrograms. This may be the explanation for the difference in sustained effectiveness between the two.

The J&J shot starts off at 71% effective and dips slightly to 68% after 30 days. Data beyond that was not given in the CDCs report, however, a second shot of J&J at six months is reported by the company to push vaccine effectiveness up to 80%. The J&J vaccine, which goes by the brand Jansen, is a different technology and initially requires only one shot. All three vaccines stimulate our immune system to produce antibodies against similar regions on the virus spike protein which is the protein that the virus uses to gain access to our cells.

The FDA and CDC will consider the requests for booster approval by Moderna and Johnson & Johnson over the next two weeks and is expected to give a decision by the end of the month. Meanwhile, the World Health Organization (WHO) and other international health advocates are raising ethical objections to giving fully vaccinated people in wealthy countries like the US and the UK a booster shot when much of the world’s population are still waiting for their first shot. Having said that, the WHO is following the FDA’s lead and is considering approving a booster shot for the two Chinese vaccines, Sinopharm and Sinovac. If it does so, then that will further constrain the worlds vaccine supply. The United Kingdom approved a booster for AstraZeneca as well as Pfizer in early September. The European Medicines Agency (EMA), the European Union’s equivalent of the CDC, also announced last week its approval of a Pfizer booster for vaccinated people age 18 and older.

In August, the FDA expanded the age cut off down to 12 years old for the Pfizer vaccine. Consideration is ongoing about whether to further expand the age range by including children from 5 to 11. This was initially hoped for by the end of October, but now a decision is expected by mid to late November.

In the September 17th edition of the MMWR, the CDC reported the latest data comparing hospitalization and death rates for vaccinated versus unvaccinated persons in the US. To normalize for variations in the population, this is given in terms of the average per week per 100,000 people in the US. “Averaged weekly, age-standardized rates (events per 100,000 persons) were higher among persons not fully vaccinated than among fully vaccinated persons for reported cases (112.3 versus 10.1), hospitalizations (9.1 versus 0.7), and deaths (1.6 versus 0.1) during April 4–June 19, as well as during June 20–July 17.” Simply put, this continues to support the fact that being fully vaccinated makes it 10 times less likely to end up hospitalized or dead than someone who is not fully vaccinated if both people contract COVID.

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