A big day for J&J
The most important news in healthcare: Friday, March 5th
Today we’re answering one of the biggest questions of the week: what’s the deal with the new Johnson & Johnson vaccine?
Today’s Pulse is 800 words, or a 6 minute read.
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COVID-19 VaccinesThe pulse:
Last Saturday, the FDA issued an emergency use authorization for the Johnson & Johnson COVID-19 vaccine, making it the third vaccine available to the public.
What’s the difference between this vaccine and the others?
J&J’s vaccine differs from Pfizer’s and Moderna’s in four main ways: the mechanism of action, the number of doses required, the effectiveness, and storage requirements. Let’s break that down:
1. Mechanism of Action:
Both Pfizer’s and Moderna’s COVID-19 vaccines, which received emergency use authorization back in December, are mRNA vaccines. As we talked about in this Past Pulse, mRNA vaccines work by providing a molecule called messenger RNA that gives cells the ability to produce a viral protein that can trigger an immune response. J&J’s vaccine on the other hand is a viral vector vaccine. Instead of introducing a molecule of mRNA into the body, the J&J vaccine uses a harmless virus (called an adenovirus) which has been engineered to make a protein also made by the SARS-CoV-2 virus. This similarly prompts our immune systems to react by producing protective antibodies. Unlike mRNA vaccines, adenovirus vector vaccines had been approved even before the COVID-19 pandemic. In fact, J&J used the same method to produce an Ebola vaccine approved in Europe back in July of 2020.
2. Number of Doses
One of the biggest talking points has been the number of doses required -- while Moderna’s and Pfizer’s vaccines both require two doses, J&J’s is a single-dose shot. This is a big deal for a few reasons -- with overall vaccine supply still low and demand high, a single-dose vaccine could make a significant dent in the large remaining unvaccinated population. There’s also less worry about people not gaining full protection if they don’t come back for their second dose.
Source: CNBC
3. Effectiveness
However, there’s a trade-off: J&J’s vaccine does seem to be less effective than both Pfizer’s and Moderna’s. While both Pfizer and Moderna showed their vaccines to be ~95% effective at preventing symptomatic COVID-19 infection, J&J’s vaccine has been shown be to 66% effective against moderate to severe COVID-19 infection and about 85% protective against severe disease. There’s also some regional discrepancies to note: for moderate to severe infection, J&J’s vaccine was 72% protective in the United States, 66% protective in South America, and 57% protective in South Africa. However, this drop in efficacy could at least in part be due to trial design —one arm of J&J’s trial was based in South Africa, where a variant called B.1.351 was spreading. Lab studies have shown that both Pfizer and Moderna vaccines also appear to be less effective against the B.1.351 variant.
4. Storage
One of the biggest initial concerns with the mRNA vaccines from a large-scale distribution angle was the storage requirements: Pfizer’s vaccine initially had to be stored in special ultra-cold freezers, while Moderna’s vaccines could be kept at temperatures more similar to a normal freezer. J&J’s can be stored at refrigerator temperatures (2°C to 8°C) for up to three months, making it the easiest to store of the three -- another huge advantage when considering the ability to provide mass vaccination.
Okay, so what does this all actually mean from a public health standpoint?
Johnson and Johnson’s vaccine has the potential to greatly expand large scale vaccination efforts. With more lax storage requirements and the need for only a single dose, the vaccine is more amenable to large vaccination drives, which have already started in some states. Just this week, New York announced that with Johnson and Johnson’s added supply, residents can start receiving overnight vaccinations at three mass vaccination centers, including Yankee Stadium.
However, J&J’s lower efficacy rate has raised concerns about inequities in vaccine distribution, especially because early roll out has been focused on community health centers and rural communities. On the other hand, many of the populations being offered J&J’s vaccine have also been hit particularly hard by COVID-19 and could benefit the most from early vaccination. Most vaccination experts seem to agree that J&J’s vaccine is overall an important step towards reducing health disparities, not fueling them. As Dr. Rupali Limaye, a researcher at Johns Hopkins University puts it:
We’re facing disparities related to Covid. How do we reduce disparities? We get a product out that’s one dose and that’s stable.
Bottom line it for me:
The new Johnson and Johnson COVID-19 vaccine could help the US expand distribution in a way not previously possible. While the vaccine’s lower efficacy rates have raised equity concerns, most public health officials seem to agree that the single dose and simpler storage makes the vaccine an important tool in ending the pandemic for all populations.