Up to now the COVID-19 vaccines came not only with cumbersome storing requirements but also were to be injected twice after certain lapse of time to prove efficacious. These difficulties appeared to have been overcome with Johnson & Johnson preparing a single-shot vaccine that will provide a long-anticipated tool adding firepower and flexibility to the accelerating inoculation effort. It augurs well for healthcare systems that they now have three effective vaccines, a singular scientific achievement that few would have predicted a year ago, when a pandemic emerged that has killed 2.5 million people worldwide. It comes at a particularly fraught time, as people are subjected to worrying news such as the emergence of potentially menacing variants.
With demand for vaccines outracing supply and officials scrambling to get much of the population vaccinated before variants spoil an improving picture, a third vaccine is of tremendous importance. The new vaccine, which is for adults 18 and older, has clear practical and logistical advantages over the first two vaccines — it does not have to be kept frozen, and there is no need for a second round of appointments. That makes it a boon for health centres that might not have the freezers needed for the other vaccines.
The catch however is that the Johnson & Johnson shot also has a lower efficacy rate, leading some public health experts and government officials to worry that it will be viewed as substandard compared with the other vaccines. The Johnson & Johnson efficacy rate is 66 per cent overall helpful in preventing moderate to severe cases of COVID-19, the disease caused by the coronavirus. The vaccines by US pharmaceutical giant Pfizer and its German partner BioNTech and by the biotech company Moderna are about 95 per cent effective following their two-shot regimens.
All three vaccines have been shown to be fully effective in protecting against what people fear most — hospitalisations and death. Significantly, the two earlier vaccines were tested months before the emergence of variants of concern that appears to affect the efficacy of the vaccines. Infectious-disease experts placed the newest coronavirus vaccine in the context of vaccines used to thwart other infectious diseases. This vaccine carries more than 70 per cent efficacy rate whereas the FDA’s efficacy requirement is 50 per cent. However, many experts are of the view that the protection provided by the vaccine is similar to that from a single dose of Pfizer.
Some experts say it is important for people to understand that there might be differences between vaccines in preventing moderate cases of COVID-19, because even those infections could have long-term consequences and moreover, at the same time, it is observed that people prefer one shot vaccine. It must be borne in mind that for now, consumers are unlikely to have a choice of vaccines because there simply is not enough supply but this situation is poised to change in coming months. A vaccine developed jointly by the University of Oxford and AstraZeneca and another from Maryland Biotechnology Company Novavax are also in the late stages of testing that will soon be available.
In the meanwhile, addition of the Johnson & Johnson shot will diversify the portfolio of vaccines, adding one that works through a different scientific technology. The Pfizer-BioNTech and Moderna vaccines employ an approach that had never been used in people outside of clinical trials. They deliver a strip of genetic material called messenger RNA carrying the instructions to build the spiky protein found on the outside of the virus. In contrast, the Johnson & Johnson vaccine uses a harmless cold virus to deliver a gene encoding the spike protein to cells. The approach is more established. In both cases, cells follow genetic instructions to construct the spike and the immune system learns to recognise the real thing from these replicas — and to respond. The latest vaccine will also add a new supply stream to help alleviate shortages or manufacturing delays. A different process and supply chain are used, which could help bolster confidence that if any of the vaccines runs into production difficulties, there will still be supply.
The advantages of each vaccine against the pathogen are still being untangled. Although a single shot of the Johnson & Johnson vaccine did not trigger antibody levels to soar as high as a two-dose regimen, it offered good protection against variants. Scientists think that could be because the vaccine robustly triggered another arm of the immune system, T cells, that may provide a different layer of protection.
For scientists who have long worked on vaccines, the scale and velocity of the coronavirus research has been stunning as during the HIV vaccine trials as many as 5,000 participants were involved but the Johnson & Johnson study recruited 44,000 people in about 2½ months. Since everybody is at risk therefore it was easy to enroll people. The Johnson & Johnson study also might help elucidate some questions that are beginning to arise from real-world use of the vaccines particularly mixing and matching process that may begin to occur in the future, particularly as companies begin testing additional booster doses as a way to protect against variants. TW