The latest American COVID-19 vaccine, Novavax, now joins Sputnik V, Pfizer and Moderna in achieving record high levels of efficacy — all in the mid-90% area. Final clinical tests with 30,000 volunteers in the United States and Mexico showed 96.4% efficacy against the original virus, and a solid 86.3% against variants. And Novavax’s production is set to go for around 600 million doses this year, primarily from the Serum Institute of India, but also from Spain and Poland. Novavax’s vaccine is a “protein subunit” vaccine, along the lines of vaccines for hepatitis B and pertussis. It can be stored at refrigerator temperatures.
Unfortunately, Germany’s CureVac, tested amongst 40,000 volunteers in Europe and South America, is showing efficacy levels around 47% in two different preliminary findings. While a substantial proportion of variants, including the highly transmissible delta variant, are thought to be dragging down the efficacy levels, that can’t be the whole story, as other vaccines are achieving levels against the variants in the 80-90% range. It is of concern, as the European Union had contracted for up to 225 million doses this year, with an option for another 180 million; and now that appears in jeopardy.
India’s Zydus Cadila announced July 1 their results of clinical trials of their plasmid DNA vaccine: 66.6% effective against symptomatic cases, and 100% against moderate disease. It is a genetically engineered plasmid containing the DNA sequence of the SARS-CoV-2 spike protein. It is also needle-free, delivered through the skin by a jet of air, which can be an advantage given the present bottleneck in the production of needles and syringes.
