Eight different Covid-19 vaccines are currently being used around the world and just over 172 million people have received their first dose, 2.2 for every 100 people. All of the vaccines being used require two shots but that is set to change with Johnson & Johnson’s JNJ+0.3%JNJ+0.3% one-shot vaccine expected to gain regulatory approval for use in the United States within weeks. As it stands, the first Covid-19 vaccine to be authorized for use in the U.S. is also the most widely used shot globally, according to information from website Our World in Data reported by The New York Times.
Just two months ago, the incredible performance of new vaccines from Moderna and Pfizer had people cheering for an imminent end to the pandemic. But an onslaught of fast-spreading and potentially dangerous mutations of the virus changed that.
So now, even as pharma companies ramp up production in the early stages of a massive rollout, they are racing to retool their vaccine strategies. Robert Langreth reports that booster shots could give drugmakers a lucrative new revenue stream.
As Covid-19 vaccines roll out in several countries, counterfeits are being marketed online. WSJ explains how phony vaccines end up on the internet and the risks for people who buy them. Illustration: Crystal Tai
How does each of the available Covid-19 vaccines work?
Once the vaccine is injected, the mRNA is taken up by the macrophages near the injection site and instructs those cells to make the spike protein. The spike protein then appears on the surface of the macrophages, inducing an immune response that mimics the way we fight off infections and protects us from natural infection with SARS-CoV-2. Enzymes in the body then degrade and dispose of the mRNA. No live virus is involved, and no genetic material enters the nucleus of the cells.
Although these are the first mRNA vaccines to be broadly tested and used in clinical practice, scientists have been working on mRNA vaccines for years. And despite this wonderful parody piece. opens in new tab saying that the technology is “obvious,” in fact the breakthrough insight that put the mRNA inside a lipid coating to prevent it from degrading is quite brilliant — and yes, this may be the first time the New England Journal of Medicine has referenced a piece in The Onion. (Last reviewed/updated on 11 Jan 2021)
How should early side effects be managed?
Analgesics and antipyretics such as acetaminophen or ibuprofen are effective in managing post-vaccine side effects including injection-site pain, myalgias, and fever. However, the CDC does not recommend prevaccine administration of these drugs, as they could theoretically blunt vaccine-induced antibody responses.
Because of the small risk of anaphylaxis, sites that administer the vaccines must have on hand strategies to evaluate and treat these potentially life-threatening reactions. The CDC has issued recommendations on how sites should prepare. opens in new tab. (Last reviewed/updated on 11 Jan 2021)
How long will the vaccines work? Are booster doses required?
Since the vaccines have been tested only since the summer of 2020, we do not have information about the durability of protection. Data from the phase 1 trial of the Moderna vaccine suggested that neutralizing antibodies persisted for nearly 4 months. opens in new tab, with titers declining slightly over time. Given the absence of information on how long the vaccines will be protective, there is currently no specific recommendation for booster doses. (Last reviewed/updated on 11 Jan 2021)
Do the vaccines prevent transmission of the virus to others?
Many commentaries on the results of the vaccine clinical trials cite a lack of information on asymptomatic infection as a limitation in our knowledge about the vaccines’ effectiveness. Indeed, this is a theoretical concern, since up to 40% of people who get infected with SARS-CoV-2 have no symptoms but may still transmit the virus to others.
Nonetheless, there are several good reasons to be optimistic about the vaccines’ effect on disease transmission. First, in the Moderna trial. opens in new tab, participants underwent nasopharyngeal swab PCR testing at baseline and testing at week 4, when they returned for their second dose. Among those who were negative at baseline and without symptoms, 39 (0.3%) in the placebo group and 15 (0.1%) in the mRNA-1273 group had nasopharyngeal swabs that were positive for SARS-CoV-2 by RT-PCR. These data suggest that even after one dose, the vaccine has a protective effect in preventing asymptomatic infection.
Second, findings from population-based studies now suggest that people without symptoms are less likely to transmit the virus to others. Third, it would be highly unlikely in biological terms for a vaccine to prevent disease and not also prevent infection. If there is an example of a vaccine in widespread clinical use that has this selective effect — prevents disease but not infection — I can’t think of one!
Until we know more, however, we should continue to emphasize to our patients that vaccination does not allow us to stop other important measures to prevent the spread of Covid-19. We need to continue social distancing, masking, avoiding crowded indoor settings, and regular hand washing. (Last reviewed/updated on 11 Jan 2021)
Electors around the country are heading to their state capitol buildings today to formalize President-elect Joe Biden’s election win. It’s normally a big ceremonial event, where guests and members of the public are welcome to watch the vote. But this year – masks, social distancing and police escorts will make it look a lot different.
- Plus, an explainer on Brexit’s latest delay.
- And, we take you inside a Michigan warehouse shipping out the vaccine.
Guests: Axios’ Stef Kight, Dave Lawler and Joann Muller.
Radio News 24/7 reports: Pfizer vaccine approved by FDA, Germany faces surging Covid-19 fatalities, and other top world news.