Covid saga continues
Dr Asha Shah. M.D. Professor of medicine
GCS Medical college, Ahmedabad
We are already in seventh month of 2020. Already beyond half way mark and Covid is still very much thriving. In the history of mankind, year 2020 will be known as Covid era. It is the year of pandemic, global diseases, deaths, despair, depression, fear, anxiety, poverty, instability, insecurity and what not. The pandemic is going strong causing immeasurable pain and suffering on is wake and is still unabated. Nobody on the Earth can predict its course. All the epidemiologists and mathematicians who predict its course by building mathematical model are also clueless because there are so many factors affecting it. There are so many variables and ones of the most important is the behavior of people which is the most unpredictable and which can make all the difference.
There are so many things unexplained in this situation.
In developed world the handling of the pandemic and behavior of people is differing in different countries. The age group of people affected is different at different times and in different countries. Each country had different scenarios in different states. Mortality is different too. As it is a new disease, people are also learning about it. Even with all the advancement, they are also struggling to control the disease though situation is better in Europe. Even now the Covid cases are 60000 in a single day in US and around 30000 new cases in India/day and will reach one million mark very soon.
In India somehow cases are less compared to the huge population and the density of it but it is now near I million mark with doubling time of 20 days, it may still explode. Still more mysterious is the less number of deaths compared to western countries. It may be explained on the basis of different strain of virus having different virulence (L type compared to S type) but scientists have ruled out theory of different strains. According to them, they are just linages and called clades but different researchers say that there is no proof that the clades have any effect on virulence but again it is confusing and unless it is traced , it cannot be known certainly.
Similarly the incidences are different in neighboring countries also.
Is there a hope for herd immunity?
One thing seems certain. This year is Covid year and will remain so. The tail of the pandemic is nowhere in sight. Herd immunity is not a likely to develop. In Spain, there were huge numbers of cases as they wanted herd immunity to kick in and did not go for lock down. In a study carried out subsequently, only 5% of population was antibody positive. It is not even known how effective the protective immunity is and if so for how long.
The virus mutation , D versus G variant.
The SARS coV2 virus has believed to have undergone minor mutation 198 times but only one is considered significant. About 1,300 amino acids are present on the protein on the surface of the virus. In the mutant virus, the genetic instructions for just one of those amino acids — number 614 — is switched in the new variant from a “D” (shorthand for aspartic acid) to a “G” (short for glycine)as per the new paper, published July 2 in the journal CELL, The study finds that virus particles with this mutation can enter into cells easily, suggesting that it is outcompeting other strains of the virus to become the dominant version of SARS-CoV-2 in Europe and US while D variant was present in initial cases in Wuhan. Other, experiments have found similar results. Patients with the G variant actually have more viruses in their bodies, making them more likely to spread it to others. G variant’s spread in Europe and the U.S. was really fast. This virus was approximately 6–7 times more infectious in the lab experiment though mortality did not show much change.
The hope for vaccine
Whatever the claims, realistically speaking vaccines are not likely to be available in market before the year end as per prediction from numerous researchers and endorsed by WHO scientist Sowmya swaminathan in a TV interview but we still keep on hearing about imminent availability of vaccines from different countries.
New modes of transmission
We are discovering new modes of transmission like the airborne one particularly in enclosed spaces and also that it can be transmitted by flushing the toilet as it is excreted in faeces. Turbulence from a toilet bowl can create a large plume that is potentially infectious to a bathroom’s next visitor. It is also reported that in some cases where diarrhea was the dominant symptom, throat swab was negative but rectal swab was positive .There is a documentation of intrauterine transmission of covid 19 in Texas before few days, where a baby born to Covid positive mother had symptoms of Covid 19 and the 1 day old infant was tested Covid positive too and the virus was detected in placenta..So we are still learning about routes of transmission.
Co infection with Dengue or Malaria
Now in India, there will be surge of cases of dengue and malaria due to monsoon. We don’t know how the co infection with Covid 19 will turn out as during this season we come across simultaneous vector borne multiple infections in patients. Both these disease also produces thrombocytopenia or low platelets and involve other systems of body. There will also be increase cases of disease like enteric fever(Typhoid). In winter flu season also will start. Apart from causing dilemma in diagnosis, it may pose problems in treatment and it might be a unique problem in India or other developing countries. We have to wait and see.
Treatment of Covid
We are discovering new use of old medicines. There is lot of controversies there. Much hyped drug HCQ( Hydroxychloroquine) for the treatment of Covid was not found effective and is dropped from Solidarity Trial which is one of the important global trials to assess the efficacy of 4 different groups of drugs. ICMR (Indian council for medical research) recommended HCQ for prophylaxis of COVID in health care workers and contacts of positive patients. They have come out again in May that after in vitro experiment of drug by NIV Pune and trial of health care workers in AIIMS new Delhi .They found less incidence of Covid in those health care workers who were on HCQ prophylaxis compared to those who were not. So ICMR has continued recommending HCQ in the select group of population for prophylaxis. Steroid is recommended for use after the trials in UK showed its effectively in reducing mortality in select patients. We, in India were using methyl prednisolone(A form of steroid) in patients of suspected cytokine storm which may also account for less deaths in certain group of patients. Fortunately some old drugs having some antiviral efficacy against Covid (Ramdesivir and fevipiravir ) are available now in the market though with some difficulty. They may reduce the duration of illness but have no effect on mortality. They are of help in moderate disease. Convalescent plasma is also a part of treatment strategy. Injection Tosilizumab is helpful in treating cytokine storm and one more drug Itozulimab (Monoclonal antibody) which was used for treatment of psoriasis is allowed for restricted emergency use by drug controller of India to treat Covid 19 patients with moderate to severe acute respiratory distress .The approval was given after clinical trials.
Ahmedabad scenario
One thing seems hopeful. That may be the silver lining. The deaths are decreasing in Ahmedabad and the Covid cases are also decreasing though in Gujarat they are increasing and that is difficult to explain. In Gujarat they are above 800 per day but in Ahmedabad they are less than 200 cases. We can say that many mild cases may be staying home and not getting tested. That is a possibility but deaths are now in single digit in Ahmedabad and that is certain and encouraging though not explainable. Even in the world, mortality numbers are low as compared to that in months of March and April. That is very good to know but hard to explain.
Life style change continues
So the numbers are either not encouraging or not explained but the fact is that our life style has changed for the worse and that nobody can deny. We live under constant fear and stress, worried that it may affect us and we will be caught unaware. Social life has come to standstill but people are so desperate that they take risks. No celebration can be planned. People who had planned weddings in December 2020 also cannot probably hope to do it. All the festivals which will now start will not be celebrated on a large scale. Travel is totally not imaginable. Those parents whose children are away worry about them and also scared as they are uncertain when they will be able to see them .That uncertainty is definitely greatly disturbing. Life itself is uncertain and Covid has made us all realize that surely. We are not sure when it will be possible to travel or fly safely. We are not sure when it will be possible to open up the teaching institutions. All the exams are postponed or their style is altered. Academics will definitely go down.
Will Miracle happen one fine day?
Everything can change one fine day. If we get effective vaccine, that will be the day to look forward to. Oxford university trial, Moderna from US, Russian company etc. are in various stage of trials and some may even go for phase 3 trial. We should be proud that two Indian companies have reached the advance stage with the development of vaccines and are conducting human trials of vaccines. As these vaccine trials are mostly single dose and short period study, they can advance into the next stage comparatively faster. If they show adequate and lasing immunogenicity and no side effects and if they are available in sufficient quantities, they may turn into reality. That is the day to look forward to. That will be the light at the end of the tunnel. Once the situation will be controlled, everything will bounce back. It seems improbable now but it may happen in future that we may forget this horrible period as a nightmare. We are all so worried about economy but it can also be better in 6 months. The only hurdle and a major one is for the disease to phase out. Meanwhile we have to continue the preventive measures and there is absolutely no option for that.
https://www.livescience.com/new-coronavirus-mutation-explained.html
https://www.washingtonpost.com/science/2020/06/29/
