Getting the vaccine does not mean you can’t get infected, get very sick, or transmit the virus to others. That’s why, according to the CDC, you have to continue wearing a mask and social distancing. The vaccine was only designed to lessen mild symptoms. It was not designed or tested to prevent serious illness or to prevent transmission. The vaccine manufacturers should be making this point more forcefully in the media.
Will Covid-19 Vaccines Save Lives? Current Trials Aren’t Designed To Tell Us, British Medical Journal, 21 October 2020
Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, said, “Ideally, you want an antiviral vaccine to do two things . . . first, reduce the likelihood you will get severely ill and go to the hospital, and two, prevent infection and therefore interrupt disease transmission.”7
Yet the current phase III trials are not actually set up to prove either (table 1).
None of the trials currently under way are designed to detect a reduction in any serious outcome such as hospital admissions, use of intensive care, or deaths. Nor are the vaccines being studied to determine whether they can interrupt transmission of the virus.
Yet until vaccine manufacturers began to release their study protocols in mid-September, trial registries and other publicly released information did little to dispel the notion that it was severe covid-19 that the trials were assessing. Moderna, for example, called hospital admissions a “key secondary endpoint” in statements to the media.15 And a press release from the US National Institutes of Health reinforced this impression, stating that Moderna’s trial “aims to study whether the vaccine can prevent severe covid-19” and “seeks to answer if the vaccine can prevent death caused by covid-19.”16
But Tal Zaks, chief medical officer at Moderna, told The BMJ that the company’s trial lacks adequate statistical power to assess those outcomes. “The trial is precluded from judging [hospital admissions], based on what is a reasonable size and duration to serve the public good here,” he said.
“Our trial will not demonstrate prevention of transmission,” Zaks said, “because in order to do that you have to swab people twice a week for very long periods, and that becomes operationally untenable.”
Great uncertainty remains over how long a randomised trial of a vaccine will be allowed to proceed. If efficacy is declared, one possibility is that the thousands of volunteers who received a saline placebo would be offered the active vaccine, in effect ending the period of randomised follow-up. Such a move would have far reaching implications for our understanding of vaccines’ benefits and harms, rendering uncertain our knowledge of whether the vaccines can reduce the risk of serious covid-19 disease and precluding any further ability to compare adverse events in the experimental versus the placebo arm.
If frail elderly people, who are understood to die in disproportionate numbers from both influenza25 and covid-19, are not enrolled into vaccine trials in sufficient numbers to determine whether case numbers are reduced in this group, there can be little basis for assuming any benefit in terms of hospital admissions or mortality.
This is hard to evaluate in the current trials because there are large gaps in the types of people being enrolled in the phase III trials (table 1). Despite recruiting tens of thousands, only two trials are enrolling children less than 18 years old. All exclude immunocompromised people and pregnant or breastfeeding women, and though the trials are enrolling elderly people, few or perhaps none of the studies would seem to be designed to conclusively answer whether there is a benefit in this population, despite their obvious vulnerability to covid-19.
Al Sommer, dean emeritus of the Johns Hopkins School of Public Health, told The BMJ, “If they have not powered for evidence of benefit in the elderly, I would find that a significant, unfortunate shortcoming.”
One view is that trial data should be there for all target populations. “If we don’t have adequate data in the greater than 65 year old group, then the greater than 65 year old person shouldn’t get this vaccine, which would be a shame because they’re the ones who are most likely to die from this infection,” said vaccinologist Paul Offit.8 “We have to generate those data,” he said. “I can’t see how anybody—the Data and Safety Monitoring Board or the FDA Vaccine Advisory Committee, or FDA decision-makers—would ever allow a vaccine to be recommended for that group without having adequate data.”
“I feel the same way about minorities,” Offit added. “You can’t convince minority populations to get this vaccine unless they are represented in these trials. Otherwise, they’re going to feel like they’re guinea pigs, and understandably so.”