The recent US approval of a third safe, highly effective COVID-19 vaccine could help accelerate a mass vaccination effort that represents a bright spot in the long tragedy of the pandemic.
Tests of the new, one-shot vaccine by Johnson and Johnson show it may be slightly less effective in preventing infections than the two existing approved vaccines, but at least as effective in preventing serious illness, deaths and hospitalizations.
Moreover, the one-shot vaccine requires much less careful handling, giving it important advantages in a mass-inoculation campaign — especially in countries that lack the medical infrastructure of the US.
Finally, some evidence suggests the Johnson and Johnson vaccine may perform better than the two other approved US vaccines when it comes to preventing infection by some of the more troublesome mutations of the virus.
The big catch right now remains slow production of the Johnson and Johnson vaccine. The US paid $1 billion to help develop the vaccine in return for the guarantee of 37 million doses by the end of March and 100 million by the end of June. However, the company’s having trouble scaling up production at its Baltimore plant.
The US also has commitments from Moderna and Pfizer to provide enough shots to inoculate 300 million people by sometime this summer. The US is currently inoculating 1.7 million people daily.
Worldwide, 10 rich nations have so far bought up 75% of the available vaccines. In some 130 other nations with 2.5 billion people, not a single dose has been received. The US invested $4 billion in return for the promise of enough shots to vaccinate the entire population two times over.
The limited statistics coming out of the clinical trials make it difficult to directly compare the three different vaccines approved for use in the US. Several other vaccines are in use in other countries. The FDA committee that unanimously approved use of the Johnson and Johnson vaccine reviewed figures that showed Pfizer and Moderna’s two shots were 95% effective in protecting against symptomatic COVID disease, while Johnson and Johnson’s vaccine was 72% effective against moderate to severe disease. The clinical trials for each vaccine defined the measured endpoints a little differently.
None of the clinical trials have yet determined whether any of the three vaccines also make it less likely that a person who gets the shot can still infect others. The preliminary results suggest the shot sharply reduces, but does not eliminate, the odds of infecting others. Many other vaccines that don’t confer so-called “sterilizing immunity” can nonetheless stamp out the disease — including the polio vaccine.
US nursing homes have seen an 80% drop in new infections since vaccines started in mid-December and Israel has vaccinated more than half of its population and seen a 49% decrease in new cases among those over 60.
Health officials say it’s still critical to continue wearing masks in public and in group activities as the vaccination program moves us towards “herd immunity.”
The spread of new strains of the virus that causes COVID have raised additional concerns, since a number of those strains both spread faster and cause more serious disease. Genetic screening has so far identified at least 300 new COVID cases in Arizona caused by one of the new strains. The CDC estimates that one or more of the faster-spreading strains will become the dominate strain in the US by April.
The preliminary evidence suggests that some of those new strains may either reinfect people who have recovered or infect a larger share of the people who have gotten vaccinated. Even in those cases, all three approved US vaccines provide better protection than most shots for other diseases. Evidence suggests even if people get reinfected with one of the new strains, they’ll likely develop much less serious disease.
Some evidence suggests the Johnson and Johnson vaccine may hold up better against new stains than the Pfizer or Moderna vaccines.
The Johnson and Johnson vaccine works by using a modified cold virus to deliver a strand of DNA from the COVID-19 virus. The modified cold virus can’t reproduce, but it can insert the DNA strand into a cell.
The cell then begins to manufacture the protein spike that bristles from the surface of the COVID virus. This protein triggers a cascade of immune system reactions. Immune system antigen-presenting cells take up the spike protein and present it to other cells, which raise the alarm. Helper T-cells, B cells, Killer T-cells, and memory B-cells all get activated. As a result, when the actual virus shows up, the immune system springs into action immediately — wiping out the virus before it can get a foothold.
The Pfizer and Moderna vaccines both operate by injecting a tiny sequence of messenger RNA with the instructions for the spike protein. The double strand DNA used in the Johnson and Johnson vaccine may somehow prepare for a wider variety of virus strains than the single-strand RNA molecule from the Pfizer and Moderna vaccines.
All three of the approved vaccines have only minimal side effects.
In the clinical trials of the Modern and Pfizer vaccine, 80% said the shot made their arm sore or caused some other fleeting reaction like fever or fatigue, according to a summary of research on side effects published in the scientific journal Nature. People report more symptoms for the second shot, most of them fleeting and minor.
Some deaths have been reported following the Pfizer and Moderna vaccines, but the deaths haven’t been linked to getting the shot.
The Pfizer and Moderna vaccines have triggered a serious allergic reaction in between three and five shots out of a million, a bit higher than most vaccines. Some reactions have required hospitalizations, but all patients have fully recovered. A shot of epinephrine normally heads off the reaction quickly, which is why vaccination sites ask people to wait for 15 minutes after getting the shot. The reaction may be triggered by an ingredient in the oily capsule that encases the fragment of messenger RNA rather than by the spike protein., the research summary concluded.
None of the reactions to any of the vaccines compare to the risks of infection, which has caused death in between 1 and 2% of the confirmed cases, killing at least 514,000 Americans so far.
All three vaccine manufacturers are conducting additional trials on whether people under 18 also benefit from the shots, as well pregnant women. All three are also testing the effect of the shots on the growing number of new strains. They’re also gathering data on whether immunity trails off over time. Some types of vaccines offer permanent immunity, others require booster shots – depending on how quickly the virus in question evolves.
Still, the results are all preliminary — and underscore the importance of reaching herd immunity as soon as possible.
In the meantime, health officials urge people to wear masks in public and avoid gathering in close, indoor quarters with poor ventilation or even large, outdoor setting with lots of people jammed in together.