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)
Messenger RNA—or mRNA—vaccines have been in development for decades, and are now approved for use against COVID-19. Here’s how they work and what you should know about them. Visit https://www.jhsph.edu/covid-19 for even more resources.
Over the course of the pandemic, scientists have been monitoring emerging genetic changes to Sars-Cov-2. Mutations occur naturally as the virus replicates but if they confer an advantage – like being more transmissible – that variant of the virus may go on to proliferate.
This was the case with the ‘UK’ or B117 variant, which is about 50% more contagious and is rapidly spreading around the country. So how does genetic surveillance of the virus work? And what do we know about the new variants? Ian Sample speaks to Dr Jeffrey Barrett, the director of the Covid-19 genomics initiative at the Wellcome Sanger Institute, to find out Coronavirus – latest updates See all our coronavirus coverage.
Human Papillomavirus, HPV, is a very successful Virus, from the microbial standpoint. It has been around for a long time, specializes in Humans, kills many fewer than it infects and becomes a chronic disease, even if 90% of infections resolve spontaneously within 2 years.
HPV is a DNA Virus. Most of the strains, if they persist, become harmless nuisances, and cause “Verruca Vulgaris”, the common wart of the skin. The voicebox and windpipe area is rarely targeted, but warts can produce problems there because of the location. Non-malignant genital warts can also occur with certain serotypes.
A few members of the HPV family have evolved to generate premalignant lesions that can develop into CANCER. These strains are spread by Sexual contact. In Women, the CERVIX of the Uterus or the vagina are often involved. The anal area, back of the throat and the Lung are occasional sites in both sexes. In Men, the Penis is targeted.
Cancer is generally a delayed effect that occurs after a long infection. Some HPV strains, such a 16 and 18, have evolved to suppress the p53 gene, an ONCOGENE which protects us from malignant progression. Without this protection, a chance cancerous mutation can grow without restraint. Since HPV can invade only the deeper basal stem cells in the skin or lining mucous membranes, some minor trauma or break in the surface is needed to allow Viral entry.
If antibodies are present, the Virus is intercepted, and infection doesn’t take place. This discovery made Immunization with the Cancer-producing strains attractive. It is also why the immunization is recommended in Childhood, before Sexual activity begins. Immunization after the HPV is already inside the body is Ineffective.
The Virus is already in the Nucleus of infected cells and protected from the immune response. The recommendation is to get the immunization in childhood, and use condoms.
Its decision time for Covid vaccines, especially for 88-year olds. The choice is among live-attenuated vaccines, whole virus vaccines, Split virus vaccines, and RNA vaccines, and I prefer the latter because of its simplicity. It delivers just the mRNA coding for covid spike protein, without the risk of a live vaccine, and the extra substances in whole and split- virus vaccines.
mRNA utilization for a vaccine is not new technology. The idea has been floating around for decades in cancer immunotherapy research. The sophisticated understanding of the technology is reassuring. It has a high efficacy, approaching 95%. Between the Pfizer and Moderna mRNA vaccines, I prefer the Moderna vaccine, because the Company was already working on a mRNA platform for MERS, a Covid-family virus, and has developed their own lipid capsule as a vector.
The Moderna vaccine does not require the extremely low storage temperatures like the Pfizer product. With all production located within the company, Moderna will be ready to go if a new strain nullifies covid 19 vaccines, or if another virus spreads worldwide. Timing is important. The mRNA vaccine requires 2 doses. I intend to take the first Moderna dose when I can get it locally without standing in line.
Since I intend to continue Masking and Distancing until the cases in my community are low, I will probably delay the second dose until summer, to increase my likelihood of effective antibody levels this coming fall and winter. Also, there will be more information by that time on the Vaccine’s effectiveness and duration in the Elderly.
The pathogenicity of the English, or any other newly mutant strain will be hopefully known by Summer. The rapid Covid test using sputum, and outpatient treatment with monoclonal and convalescent antibodies for early cases will then be available. I want a treatment plan in case I get infected. This is a treacherous, nasty infection.
This video tells the story of Ana, a cervical cancer survivor, who encourages women to recognize abnormal Paps as an opportunity to speak to your doctor about gynecologic health.
Virologist Angela Rasmussen talks about her battle against misinformation in the media, the virus, vaccines, disinfecting surfaces, home testing, and the next pandemic.
Eric J. Topol, MD: Hello, I’m Eric Topol for Medscape, and this is Medicine and the Machine. I’m so glad to have my colleague and partner in this podcast, Abraham Verghese, with me from Stanford. Today, we have the rarefied privilege to discuss the whole pandemic story, the virus and vaccines, with one of the country’s leading virologists, Dr Angela Rasmussen. Welcome, Angie.
Angela L. Rasmussen, MA, MPhil, PhD: Thank you so much for having me, Eric. It’s wonderful to be here.
This podcast rectifies the blizzard of variously valid COVID information blaring on the media today, and adds to the discussion. Virologist Angela Rasmussen talks about several interesting aspects of the pandemic. BSL laboratories are discussed. BSL refers to Biological Safety Level. If a lab is dealing with a dangerous pathogen, like the hemorrhagic fever viruses, a level 4 lab is required.
“Moon suit”- like positive pressure encasements, special hoods and disposal devices are required to ensure containment of the organisms, and to prevent their escape into the environment.
She discussed the differences between live viruses, detected by PFUs (plaque-forming units) on a sheet of living cells, and what the available Covid tests pick up, namely RNA which may or not be infective. Saliva vs nasal swab samples, PCR vs antibody tests were compared. She explained what the “cycle number” in PCR tests refers to, and its significance She then discussed “fomite” transmission, and observed how hard it was to experimentally prove.
Aerosol transmission is thought more likely. Also discussed is how lucky we were that this Pandemic involved a Coronavirus, instead of another viral family that was less studied. Moderna, for instance, was in the process of developing a MERS ( a Coronavirus) Vaccine. She finished up with the observation that distancing and masks, although imperfect, are still useful.
Walmart, America’s largest grocer, launched a primary care clinic called Walmart Health, in September 2019. Analysts say the big box retailer faces several hurdles in its quest to scale up nationally with a roster of highly paid doctors and dentists. But with more than 35 million people uninsured as of 2019, and millions more with high deductible health plans, could Walmart Health’s low price point be the future of healthcare in America?