New data on using the J&J vaccine to boost itself

New data on using the J&J vaccine to boost itself

Image of injection syringes.

Based on various measures, the Johnson & Johnson COVID-19 vaccine has appeared to be less effective than a vaccine based on mRNA technology. It is also associated with some rare blood clotting complications, which is why the CDC recently revised its support of the vaccine. Nevertheless, the vaccine is easy to produce, transport and store, and there has been some indication that it offers longer-lasting protection than some alternatives. And there have also been indications that at least some efficacy difference has come from its use as a single-dose vaccine.

With all vaccines now expected to include a booster after the initial vaccine dose, we are beginning to understand how the J&J vaccine performs in multiple doses. Preliminary results indicated that a J&J vaccine boosted by mRNA dosage provided a major increase in protective antibodies. But the combination of J&J/J&J didn’t seem as effective.

However, recent research pre-printing may indicate that the protection increases over time, engages non-antibody-producing immune cells, and offers some protection against the omicron variant.

change over time

One of the manuscripts tracks a much larger clinical trial that involved giving South African health workers a second dose of J&K vaccine six to nine months after their first dose. The timing of the trial meant that many participants were outnumbered shortly before Omicron infections peaked in that country.

The team tracked test results in participants, and adjusted the data for confounding factors such as age and known risk factors. Based on the need for hospitalization, the booster was clearly effective, and its efficacy increased over time. In the two weeks following the boost, the effect in preventing hospitalization was 63 percent. After the two-week mark, however, it rose to 84 percent, and remained there for at least two months thereafter.

This increase in efficacy occurred even as Omicron was displacing Delta as the primary source of new infections in South Africa. So this appears to be in line with other results which indicate that boosters help to provide much greater protection than the initial vaccination dose alone.

This protection comes despite the fact that the levels of antibodies produced by the J&J vaccine are lower than those seen with mRNA vaccination. As a result, the South African researchers suggest that their results “indicate that protection against severe disease may be due to cellular immunity and immune memory, rather than neutralizing antibodies.” Which brings us to the second preprint, which looks at cellular immunity provided by the immune system’s T cells.

for a tee

This is a very small study, involving only 20 participants from the Boston area. But it looks at the immune response in far more detail. It also looked at people who received either one or two doses, but because of the small population of the study, there are not enough people in either group to analyze these populations separately.

In any case, antibodies exhibit a moderate but prolonged response, reaching their peak about two months after vaccination. Their levels at 240 days were almost double the levels seen one month after vaccination. Neutralization was also significantly stronger against the delta variant, less than a third of the response against the initial strain.

But the startling results came when researchers looked at T cells that help identify and kill infected cells. There was essentially no difference between these individuals at any time in the investigation. There was some decline in other types of T cells, but remained strong for up to eight months. Again, these are preliminary results from a small study, but appear to be in line with other reports of longer-lasting immunity produced by the J&J vaccine.

We are still far from fully understanding the interactions of vaccine-based immunity and the differences that arise from the different forms now in circulation, as well as the different ways in which immunity is developed. But many people, both in the US and abroad, have now received the J&J vaccine, and understanding whether they face increased risks over time will be critical to managing the pandemic going forward.