This was on boston.com yesterday.
I am posting it not to prove or disprove anything [underlined](which it won’t, anyway
) but because the bolded part is something I haven’t seen discussed here (granted I might’ve missed it as I just caught up on like 12 pages).
No magic bullet
Vaccines aren’t always effective in everyone: Over the past decade, for example, seasonal flu vaccines have been effective in about 20% to 60% of people who get them.
AstraZeneca, Pfizer and Moderna say early trial data suggests their vaccine candidates are about 90% or more effective. But those rates could change by the time the studies end.
Also, the definition of “effective” can vary.
Rather than prevent infection entirely, the first COVID-19 vaccines might only prevent illness. Vaccinated people might still be able to transmit the virus, another reason experts say masks will remain crucial for some time.
Another important aspect of vaccines: They can take awhile to work.
The first shot of a COVID-19 vaccine might bring about a degree of protection within a couple of weeks, meaning people who get infected might not get as sick as they otherwise would. But full protection could take up to two weeks after the second shot — or about six weeks after the first shot, said Deborah Fuller, a vaccine expert at the University of Washington.
People who don’t understand that lag could mistakenly think the vaccine made them sick if they happen to come down with COVID-19 soon after a shot. People might also blame the vaccine for unrelated health problems and amplify those fears online.
“All you need is a few people getting on social media,” said Moss of Johns Hopkins University.
There’s also the possibility of real side effects. COVID-19 vaccine trials have to include at least 30,000 people, but the chances of a rare side effect turning up are more likely as growing numbers of people are vaccinated.
Even if a link between the vaccine and a possible side effect seems likely, distribution of shots might not be halted if the risk is deemed small and is outweighed by the benefits, said Dr. Wilbur Chen, a vaccine expert at the University of Maryland.
But Chen said public health officials will need to clearly explain the relative risks to avoid public panic.
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And just for discussion. We may be in for a bumpy ride:
But most people will probably have to wait months for shots to become widely available. The Pfizer and Moderna vaccines also each require two doses, meaning people will have to go back for a second shot after three and four weeks, respectively, to get the full protection.
Moncef Slaoui, head of the U.S. vaccine development effort, said on CNN on Sunday that early data on the Pfizer and Moderna shots suggest about 70% of the population would need to be vaccinated to achieve herd immunity — a milestone he said is likely to happen in May.
But along the way, experts say the logistical challenges of the biggest vaccination campaign in U.S. history and public fear and misinformation could hinder the effort and kick the end of the pandemic further down the road.
“It’s going to be a slow process and it’s going to be a process with ups and downs, like we’ve seen already,” said Dr. Bill Moss, an infectious-disease expert at Johns Hopkins University.
