Corona: There may not be a Vaccine at all?

Have we prepared ourselves to live and face Corona without a vaccine?

There are many virus which human being are facing without any vaccine. Hepatitis B and HIV are two such viral infections for which there are no vaccines. The Suputnik V vaccine is now a suspect because it produces symptoms as severe as the infection itself. The Oxford Vaccine is also in doubts as two patients have developed neurological problems and its trial is on hold in USA. So what will happen? Will there be a vaccine? Let us analyze various factors.

What is Corona Virus:

Corona viruses are a group of large, enveloped, positive-sense, single-stranded RNA viruses belonging to the order Nidovirales, family Coronaviridae, subfamily Coronavirinae. Twenty-six different species are known and have been divided into four genera (alpha, beta, gamma and delta) characterized by different antigenic cross-reactivity and genetic makeup. Only the alpha-and beta coronavirus genera include strains pathogenic (dangerous) to human.

History of Corona Virus:

The first known coronavirus, the avian infectious bronchitis virus, was isolated in 1937 and was the cause of devastating infections in chicken. The first human coronavirus was isolated from the nasal cavity and propagated on human ciliated embryonic trachea cellsin vitro by Tyrrell and Bynoe in 1965. However, corona viruses have been present in humans for at least 500-800 years, and all originated in bats.

Coronaviruses have long been recognized as important veterinary pathogens, causing respiratory and enteric diseases in mammals as well as in birds. Of the known coronavirus species, only six have been known to cause disease in humans: HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory virus coronavirus (MERS-CoV) The first four are endemic locally; they have been associated mainlywith mild, self-limiting disease, whereas the latter two can cause severe illness. SARS-CoV and MERS-CoV are beta corona viruses and are among the pathogens included in the World Health Organization’s list of high-priority threats (extracted from this report.)

Mutation in Corona Virus:

Viruses, especially of those types, tend to be very inventive and they adapt. This virus is new for the human population but is 96% identical to a virus transmitted within bats. That is very close. In case of HIV it has variation/mutations which are in the range of 20%. Therefore HIV in one patient can only be 80% identical to another. COVID virus is also closely related to the SARS virus, up to 95%. Therefore the possibility for the virus to change (it’s “genetic space”) is not that large. It also relates, but less closely, to another virus which emerged a few years later – the MERS virus which was even more deadly as it killed one in three people who got infected.  But it’s deadliness also proved to be the cause of it’s eradication as it killed the hosts without infecting too many hosts.

What is hepatitis?

in the 1980s, the first vaccine was developed for Hepatitis B. There is now a vaccine for Hepatitis A, but Hepatitis C has no vaccine. Similarly, HIV has no vaccine even though efforts are continuing for 30 years to develop a vaccine.

Another problem is, there are animal viruses related to coronaviruses (the feline enteric coronavirus, for example), where the vaccine proved to be dangerous. The vaccinated cats got an even more severe infection. Cant say it was similar to Sputnik V vaccine. As if all the above complications were not enough, now there are cases of reinfection emerging from around the world. The worse part is the finding that the people reinfected with the coronavirus disease 2019 (COVID-19) may suffer more debilitating symptoms of the disease than they did during their first infection.

The findings come in the wake of last week’s report that a man in Hong Kong had been reinfected with SARS-CoV-2—the first such instance of reinfection that had been documented—but in that case the virus came back in asymptomatic form.

The second case in USA involved  a 25-year-old Reno man who’d gotten mild symptoms of the disease in April but developed more severe symptoms when he got reinfected in mid-May. “Through nucleic acid sequence analysis, the viruses associated with each instance of infection were found to possess a degree of genetic discordance that cannot be explained reasonably through short-term in vivo evolution,” the investigators write in the Lancet study. “We conclude that it is possible for humans to become infected multiple times by SARS-CoV-2, but the generalizability of this finding is not known.

In USA Dr. D. Clay Ackerly, MD, MSc, an internal medicine and primary care physician in Washington, D.C., writing for Vox described how a patient of his also developed COVID-19 symptoms twice. In his opinion piece, Ackerly, too, was careful to stress that his experience is based on 1 patient only, yet he observed:

“the trajectory of a moderate initial infection followed by a severe reinfection suggests that this novel coronavirus might share some tendencies of other viruses such as dengue fever, where you can suffer more severe illness each time you contract the disease.”

A research in India by Mumbai’s Nair Hospital and Hinduja Hospital — whose four healthcare workers (HCW) were confirmed cases of Covid-19 reinfection — has found that “for all four HCWs, the second episode had more symptoms and illness that lasted longer than the first episode”.  In the study made by the Hospital along with two premier Institutes on Biological Study found the 36 mutations within 8 samples of the virus which is unusual. The variation in the mutation of Corona virus may not be as large as 20% in case of HIV and it was presumed that the small variation of 5% in corona would not be a hurdle in vaccination. But if infection itself is not sufficient to generate anti body to prevent reinfection it is difficult to say how a vaccine will generate sufficient immunity to prevent infection.  In which case there may not be a vaccine at all.

But do not lose hope. All this is yet to be investigated and there is limited data available. But these complications may delay research of vaccine.

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