Mask drastically reduces the virus load on our defences. Vaccination simulates the virus attack and stimulates our immune system. This response wanes in the absence of a successful or unsuccessful virus attack or another dose of vaccine.
UNITED WE STAND, DIVIDED WE FALL: 2020 was the year of the Virus; 2021 was the year of the fightback; 2022 can be the year of the end of the pandemic if we collectively will it. The virus is an inanimate piece of genetic material which springs to life when it infects us. We cultivate it, multiply it, and help it spread by generously sharing it with our contacts like a computer virus on our contact list. The best method to eliminate it is for all of us to show enough self-control to collectively boycott and quarantine the virus by getting ourselves and most of humanity vaccinated, using well fitted N95 masks in public areas, and avoiding nonessential travel and crowds especially indoors. All our leaders, celebrities, influencers and industries, especially the medical insurance companies should promote this message vigorously on all forms of media.
QUARANTINE AND LOCK DOWN THE VIRUS: To avoid quarantines and lockdowns we need to break the chain of transmission of the virus. To spread, the virus needs its infected host to carry it near other susceptible hosts and help it become airborne. R, the reproduction number of the virus is the average number of individuals infected by one infected individual. A value of R above 1 means the number of infected persons is increasing, whereas below 1 they are decreasing. Value of R for the coronavirus between 2 and 4 usually leads to a lockdown and disrupts our life and the economy. Instead, we can interrupt the spread of the virus by using multiple defences now available to us in the form of masks with social distancing, vaccines, testing on the slightest doubt or contact with an infected person, self-quarantine when infected and seeking early medical help.
VACCINES ELIMINATED SMALLPOX, BUT NOT COVID-19: Vaccines are effective in providing lifelong or long-term protection and in some cases elimination of infectious viruses that do not keep mutating, like smallpox, polio, measles, mumps, rubella (German measles), varicella (chickenpox) Hepatitis B vaccine, Japanese encephalitis, and rotavirus. Effective vaccines are available against rabies, but infected wild bats and stray dogs provide them a safe house. Virus infections for which we have not yet developed vaccines include chikungunya, dengue, HIV/AIDS, respiratory syncytial virus, cytomegalovirus, herpes simplex virus, etc. Influenza and SARS viruses mutate frequently enough and just enough to escape vaccine and infection stimulated antibodies and synthetic antibodies such as monoclonal antibodies. For influenza virus, models are used to predict the likely prevalent variant each year and the vaccine is updated. Too many mutations as in the Omicron variant can lead to poor long-term survival due to elimination by natural selection. If such a variant is very highly transmissible, it can out-compete other variants and then get eliminated itself which is how many epidemics in the past have ended naturally. Vaccines and tests will need to be updated to keep up with the mutating virus.
PANDEMIC WAVES AND SURGES: Classically pandemics due to new pathogens have three waves (figure 1). The first wave is by a microbe which has jumped from some other species to humans and is not yet fully adapted to humans. The second is the biggest and worst wave when a virus variant is fully adapted to humans. The third wave is usually mild as further mutations weaken the virus but allow it to escape the immune response including cross and herd immunity, and eventually the pandemic peters out. The virus then becomes endemic or extinct. Sometimes further mutation can lead to a more dangerous variant like the 2009 (H1N1) pdm09 variant during H1N1 Pandemic that caused a fourth wave much worse than the second wave (figure 2). The Omicron variant as per a Hong Kong study multiplies 70 times faster in the airways but 10 times slower in the lungs than other variants of concern. This explains why it is spreading faster, has a shorter incubation period requiring a shorter period of quarantine; and does not seem to be causing breathing problems and complications.
TRIPLE DEFENCE AGAINST AIRBORNE VIRUSES: Influenza and SARS viruses are unique in that they are the only viruses that have caused pandemics in the last hundred years. Both are airborne, mutate frequently needing repeated jabs with updated vaccines and have been the main focus of bioweapon research. We need a triple defence against these viruses.
MASK AND VACCINES: Vaccination alone is inadequate as exposure to a large number of viruses can overwhelm our immune system as has happened in UK and Israel where after successful vaccination drive, mask and social distancing mandates were withdrawn, which led to fresh waves of infection.
MASK AND HEPA FILTER: The first and most effective defence is using a well fitted N95 face mask that filters out 95% of the virus particles. Adjusting the nose clip is important as any mask not fitting the face tightly will be ineffective as air will bypass the mask around its side edges; hence children need smaller N95 masks. NIOSH N95 or N95 is the US standard for masks. Similar standards in other nations are FFP2 in Europe, KN95 in China, DS in Japan, KMOEL in South Korea, P2 in Australia & New Zealand. These also filter out other microbes, PM 2.5 dust, smoke, allergen particles. HEPA air filters are required for air conditioning/ ventilation in closed spaces like buildings, aircraft, trains and other public transport.
VACCINES: Vaccination simulates the virus attack and stimulates our immune system to produce antibodies and killer cells against the virus. This response wanes in the absence of a successful or unsuccessful virus attack or another dose of vaccine. For Covid-19 different types of vaccines have been developed much faster than ever before. These provide different targets to our immune system:
1. Only the receptor binding domain (RBD) of the spike protein by the RBD subunit protein vaccines like the Corbevax and Covovax;
2. The entire spike protein by the mRNA vaccines from Pfizer, Moderna, J&J or DNA plasmid vaccine like ZyCovD or viral vector vaccines like Covishield, Sputnik V.
3. The entire dead virus by the attenuated virus vaccines like Covaxin. Each type of vaccine has its advantages and disadvantages. There are large variations in the antibody and cellular immune responses to these vaccines. Vaccine mix and match studies are showing better results than booster doses with the same vaccine. Vaccine by nasal route will further reduce infections and transmission by providing local immunity at site of virus entry. Larger the number of unvaccinated or otherwise vulnerable populations available, the more infections and mutations will occur.
CONTACT TRACING, TESTING AND SELF-ISOLATION HALT VIRAL TRANSMISSION: Effective early detection of viral infection forms the second line of defence by preventing further transmission of the virus to other vulnerable persons. This needs quick early testing of all with early symptoms of the disease, tracing and testing of all their contacts and also a large number of random testing of the population. Social distancing, restrictions on travel and crowding are other important measures to break the chain of transmission. Laxity in these measures makes lockdowns inevitable. RT-PCR tests are a molecular test done in expensive Thermal cycle machines in large batches and check for genetic material of the virus and are the most accurate tests till now. Separate tests are available for each specific gene target of the virus such as E (Envelope), S (Spike), RdRp, N (Nucleic acid) and ORF genes. Antigen tests detect certain proteins of the virus that trigger an immune reaction. A new rapid inexpensive test RT-LAMP has been developed by ICMR-NIV Pune and released for production recently. Nucleic acid amplification tests (NAATs) detect even low levels of viral nucleic acid, are fast but more expensive. Genome sequencing is expensive and done in specialised laboratories for epidemiological studies and not for management of Covid-19. Ideally virus samples of 10% of infected individuals are sent for genome sequencing to identify the variant and mutations present, but in practice 5% or less are tested depending on the case load. Neutralising antibody tests are not to be confused with antigen tests as they estimate a person’s antibody response to vaccine or infection.
EFFECTIVELY TREAT THE INFECTED, TO AVOID DEATH AND PANIC: Early detection and appropriate treatment is important to try and prevent complications and death. Triaging of patients into those suitable for home quarantine, symptomatic medication and monitoring, those needing admission to hospital or ICU is necessary to avoid needless over burdening of health facilities. Initially many drugs including existing antivirals were repurposed for treatment. Recently specific antivirals like Molnupiravir, Ritonavir and Monoclonal antibody therapies like Sotrovimab, Ronoprave and Evusheld have become available. Steroids, blood thinners, Oxygen, ventilators continue to be needed where relevant.
NEW WORLD AND WORK ORDER: The pandemic has accelerated changes in the work order to work from home and anywhere; online education and entertainment; virtual meetings and conferences. Home delivery of essentials, products and services, including tele health services has been possible through advances in telecommunication, transport, drone, ecommerce, digital payment, automation, artificial intelligence and many other technologies. Many nations are adapting fast and prospering while other nations are lagging and deteriorating. This is rapidly changing the world order with many developed economies already affected by stagnation, now hit by lockdowns. China, which was expected to soon become the world’s largest economy now finds itself in a downward spiral of debt, lockdowns and global loss of trust. India is very dependent on China for medical and other critically important supplies. Chip shortage is affecting availability of many life-saving medical devices. India should start manufacturing semiconductors and other important components and strategically important equipment. This is India’s best chance to become a global health and services, agricultural and manufacturing, sustainable living and economic leader.
Dr P.S. Venkatesh Rao is Consultant Endocrine, Breast & Laparoscopic Surgeon.