28th February 2020
What is the likelihood of a coronavirus (SARS-CoV-2) vaccine? And of coronavirus treatments?
Placeholder post. I’m reading/ hearing a lot of contradictory views about corona vaccine/ treatment, so will try to find the answer:
The simple answer is NO.
Flu (an entirely different virus) mutates rapidly, thereby making its immunity relatively low. Each year, they create a new vaccine based on new mutations.
Coronaviruses don’t mutate as much (virtually not at all, substantively). But since they attack the outer layer of the lungs, their antibody inducement is rather erratic in the human body. Their elusive nature (only found in the epithelium of the lung) also means vaccines can’t reach them chemically.
BIG PICTURE FACTS
“2019-nCoV (now called SARS-CoV-2) is the seventh member of the family of coronaviruses that infect humans, after MERS-nCoV and SARSnCoV” [Source].
This is a very important aricle: Experts envision two scenarios if the new coronavirus isn’t contained – 4 February 2020
Here's some info I gathered. I'm extremely pessimistic about any vaccine for this: we've never had any approved vaccine for any coronavirus in the past.
I'm really keen to know the reasons for your optimism.
Thanks in advance. pic.twitter.com/afplhRPrFd
— Sanjeev Sabhlok (@sabhlok) April 11, 2020
Let's first RULE OUT the possibility of a vaccine and THEN consider viable options.
— Sanjeev Sabhlok (@sabhlok) April 10, 2020
@ScottMorrisonMP fyi: "taking a vaccine candidate all the way to regulatory approval typically takes a decade or more". The talk about 18 months is itself an idle hope. Your view about 6 months is a hallucination.
Policy should be made on reality.https://t.co/kw4fDd3mQ7
— Sanjeev Sabhlok (@sabhlok) April 6, 2020
There is a good chance that a vaccine might never emerge. Staggered and managed herd immunity while isolating the elderly and vulnerable is the only viable remedy.
— Sanjeev Sabhlok (@sabhlok) April 6, 2020
We need to assume that we WON'T get a vaccine and THEN plan public policy.
Not the way you are doing, @ScottMorrisonMP . Stop dreaming!
— Sanjeev Sabhlok (@sabhlok) April 6, 2020
THOSE WHO DON’T SEE A VACCINE ANY TIME SOON
I dont get this either. This virus is not going to go away anytime soon. If we get an effective vaccine it will be years before its rolled out effectively globally. https://t.co/rtNYzO9Di9
— Peter Collignon (@CollignonPeter) April 14, 2020
The Australian woman driving the global search for a COVID-19 vaccine has warned that there is no guarantee of success and the government must have a “plan B” to end the pandemic.
“But I do think it is important not to create unrealistic expectations. No one has ever successfully developed a coronavirus vaccine, and we still don’t have a vaccine against HIV. [Source]
“In my lifetime, I can count seven new viruses that have arrived and we don’t have vaccines for most of them yet. This is quite a common event in human history, a plague if you like, of a new virus,” Professor Ian Frazer said. [Source]
THOSE WHO ARE HOPEFUL ABOUT A VACCINE
AT PRESENT NONE OF THESE SEVEN ARE EITHER PREVENTABLE OR CURABLE:
- “No vaccine or antiviral is available for human coronavirus infections” [Source]
- “There are no specific antiviral medications approved for this disease. Symptoms are managed with supportive care.” [Source]
MY CURRENT SUMMARY ASSESSMENT
As I read more, I’ll update this assessment:
Although nothing is available today to prevent or treat coronavirus, there is a reasonable chance (not certainty) that (a) a treatment will be found before we get a vaccine; and (b) that at least one of these (vaccine or treatment) will be found in the next 12 months.
It is a good idea to not get the virus if one is above the age of 50. Preventative actions in the next 12 months could pay off in the future.
Prospect of vaccine
Virus vaccines have to be immunogenic, sufficiently stable, safe, and suitable to induce long-lasting immunity. To meet these requirements, vaccine studies need to provide a comprehensive understanding of (i) the protective roles of antiviral B and T-cell-mediated
immune responses, (ii) the complexity and plasticity of major viral antigens, and (iii) virus molecular biology and pathogenesis. There are many types of vaccines including subunit vaccines, whole-inactivated virus, vectored, and live-attenuated virus vaccines, each of which featuring specific advantages and limitations. While nonliving virus vaccines have clear advantages in being safe and stable, they may cause side effects and be less efficacious compared to live-attenuated virus vaccines. In most cases, the latter induce longlasting immunity but they may require special safety measures to prevent reversion to highly virulent viruses following vaccination. [Molecular Basis of Coronavirus Virulence and Vaccine Development – L. Enjuanes, S. Zuñiga, C. Castaño-Rodriguez, J. Gutierrez-Alvarez, J. Canton, I. Sola]
Seven coronaviruses (CoVs) have been isolated from humans so far. Among them, three emerging pathogenic CoVs, including severe acute respiratory syndrome coronavirus (SARS-CoV), Both SARS-CoV and MERS-CoV are zoonotic viruses, using bats as their natural reservoirs, and then transmitting through intermediate hosts, leading to human infections. Although a variety of vaccines have been developed against infections of SARS-CoV and MERS-CoV, none of them has been approved for use in humans. [Antivirals for Emerging Viruses: Vaccines and Therapeutics in the Virology section of Frontiers in Microbiology.]
“a coronavirus vaccine is still months — and most likely years — away.” [Source]
“several research groups have reported the development of broad-spectrum and pan-coronavirus treatment and vaccine strategies, including those effective against both SARS-CoV and MERS-CoV.” [Source, 2017]
“In the light of a dwindling interest in SARS research in the last 5 years, MERS research has contributed to advancing the development of pan-coronavirus therapeutic options that are also effectively against SARS-CoV.” [Source, 2017]
THOSE WHO BELIEVE A VACCINE IS POSSIBLE
Prospect of treatment options
An HIV protease inhibitor, lopinavir is being studied along with ritonavir for the treatment of MERS and SARS coronaviruses. The repurposed drug is already approved for the treatment of HIV infection under the trade name Kaletra [Source]
“The National Medical Products Administration of China has approved the use of Favilavir, an anti-viral drug, as a treatment for coronavirus. The drug has reportedly shown efficacy in treating the disease with minimal side effects in a clinical trial involving 70 patients. The clinical trial is being conducted in Shenzhen, Guangdong province.” [Source]
“Bruce Aylward, an assistant director-general of the World Health Organization (WHO), has stated “there is only one drug right now that we think may have real efficacy and that’s remdesivir.” It was reported on 25 February 2020 that clinical trials for this drug were in progress, with results possibly available within weeks” [Source]
An ebola drug developed by Gilead Sciences that was found to be ineffective is now being tested in phase III randomised clinical trial in partnership with China.
The trials are being performed on 761 patients in a randomised, placebo-controlled, double-blind study at multiple hospitals in Wuhan, the epicentre of the novel coronavirus outbreak. The results from the trials are expected to be available over the next few weeks.
According to a report by The New England Journal of Medicine (NEJM), remdesivir, when administered to a coronavirus patient in the US, appeared to have improved the clinical condition. [Source]
“Passive immunotherapy involving the administration of mAbs is a promising antiviral treatment and prophylactic strategy, as evident from ZMapp and palivizumab which can effectively prevent Ebola and respiratory syncytial virus infections in humans respectively” [Source, 2017]
SPECIFIC DETAILS ABOUT INDIVIDUAL CORONAVIRUSES
Middle East respiratory syndrome coronavirus (MERS-CoV)
MERS-CoV is a member of the subfamily Coronavirinae, genus Betacoronavirus, subgroup lineage 2c. Analysis of human MERS-CoV sequences has identified several circulating genotypes. These distinct genotypes are phylogenetically classified into clades A, B, and, most recently, C, which correlate with outbreaks of MERS among humans [Source]
MERS-CoV remains incapable of sustained human-to-human transmission [Source]
BACKGROUND: TYPES OF CORONAVIRUS
Although SARS-CoV and MERS-CoV are both classified under the order nidovirales and family coronaviridae, they are phylogenetically distinct, with SARS-CoV belonging to lineage B and MERS-CoV belonging to lineage C of the betacoronavirus genus. [Source, 2017]