Features

Re-infections with Covid-19:

Published

7 months ago

2020/09/5

Are they distinct possibilities?

The headline of this article appeared with a different column yesterday due to a technical problem. We apologise to our readers for the inadvertent error – Editor

By Dr.B. J. C. Perera,Specialist Consultant Paediatrician

There has been considerable debate on whether reinfections implying repeated infections with the virus SARS-CoV-2 that causes the COVID-19 disease was occurring and whether such occurrences were even possible. A reinfection is a second, third or any subsequent infection with the same virus once a person has recovered from an initial index infection. Unscrambling of those contentions were obviously extremely important from public health as well as curative health perspectives. In the not too distant past, there were some suspicious cases of possible reinfections in other parts of the world but whether those were due to a persistence of the virus in the individual, reactivation of the same illness after some time in the person or whether these were due to new second infections could not be scientifically proven with certainty. Various types of conjectures and assumptions were quite rife in the face of the ambiguity of details on the topic of reinfections.

In the human health scenario, some viruses like measles or chicken pox viruses generate virtually life-long immunity and resistance to reinfections. Second infections with these viruses are extremely rare and are almost unheard of. In the other extreme, there are viruses like those that cause the common cold, with which reinfections are extremely common. There are examples of even certain other types of human coronaviruses that cause the common cold, with the propensity to cause multiple reinfections. From a public health perspective information regarding such immunological features of an infection are absolutely vital to facilitate the formulation and implementation of preventive measures.

Being able to say for sure that there is a reinfection by another strain of the same organism depends on how reliably one could say that it is not the same original index organism that is there in the second infection. It is not easy to detect alterations in the different strains of the same organism. However, a modern technological development has made this possible. It is a technique known as genome sequencing. Whole genome sequencing is the process of determining the complete sequence of the components of an organism’s genetic structure at a given time. This technique can be used to detect differences in the genetic make-up of different strains of the same organism. When an organism undergoes any form of mutation, the new mutant will have some differences in the genome from the original index strain.

There is now convincing evidence for at least two cases, one from Hong Kong and the other from the USA, of well-documented human reinfection with SARS-CoV-2 virus. These case reports invariably generate certain questions about how commonly reinfection may occur. The cases described here have different characteristics in terms of viral genetics, timeline of reinfection and the severity of the disease. Although we can learn quite a few things from the characteristics of these two cases, it is difficult to draw firm conclusions about the clinical and public health implications of these findings.

On August 24, researchers in Hong Kong announced the first confirmed instance of human reinfection with SARS-CoV-2. It was a 33-year-old otherwise healthy man living in Hong Kong who developed three days of respiratory symptoms and was diagnosed with COVID-19 on 26th March 2020. Following recovery, he was later PCR tested twice more for SARS-CoV-2 and both tests were negative. On 15th August 2020, he was tested for SARS-CoV-2 again as a part of re-entry screening when he returned to Hong Kong from Europe. That test result was positive. He had no symptoms at the time of the second positive result. Genome sequencing revealed that the viruses isolated in March and in August were from different genetic groups, leading the study authors to conclude that the patient had been infected twice.

In the second case, a 25-year-old otherwise healthy man living in Nevada, USA, developed a respiratory viral infection and was diagnosed with COVID-19 on 18th April 2020. The patient recovered and two PCR tests for SARS-CoV-2 performed in May were negative. Then at the end of May, the patient again developed respiratory symptoms and tested positive for SARS-CoV-2 in early June 2020. Genomic sequencing revealed that the viral isolates showed a number of genetic differences between the isolates. The authors of that report concluded that based on the degrees of genetic differences between the two isolates, these were two distinct infections.

There have also been recent news reports of one case of reinfection in Belgium and one in the Netherlands, diagnosed using genome sequencing, but the scientific details of those cases were not available at the time of writing this article.

What makes these reports of reinfection different from previous reports? There have been numerous reports of patients with possible reinfection prior to this one. In April, it was reported that hundreds of people in South Korea who had recovered from COVID-19 and were retested for SARS-CoV-2, had tested positive upon retesting. To help determine whether the patients in South Korea had indeed been reinfected and if they could transmit the virus, researchers attempted to culture SARS-CoV-2 from retest samples and traced the close contacts of those with positive retest results. The virus could not be cultured and there were no confirmed COVID-19 cases among contacts, suggesting that the detected virus was not alive. It was therefore thought that what was observed in South Korea was prolonged shedding of SARS-CoV-2, a phenomenon that is now well recognised.

The best way to establish proof of reinfection is to perform genome sequencing. The technique determines the order of chemical building blocks that comprise the genetic code of an organism. Although the genomes of different SARS-CoV-2 individual virus particles are very similar to each other and hence identified as SARS-CoV-2 and not as other viruses, some differences do occur. Those differences develop through mutations, or the substitution of one chemical building block for another, as genome copies are made. Mutations may be inherited by the next generation of virus particles, resulting in viral evolution as they accumulate over time. Genome sequencing can thus help to determine whether two populations of SARS-CoV-2 evolved separately from each other or whether one gave rise to the other. This principle can be applied to virus samples obtained from a single person at two different times.

Thousands of genome sequences of SARS-CoV-2 isolates from all over the world have been published in on-line databases. Comparison and analysis of these sequences has resulted in the characterization of several clades. A clade is a group of organisms that can be traced to a common ancestor and all common descendants. These clades of SARS-CoV-2 have geographic specificity in part because viral evolution has occurred after SARS-CoV-2 has been transported between continents. It has been found that viruses from one lineage, clade G, predominate in Europe and the United States, while clade L, the progenitor of clade G, predominates in Asia. In the case of the Hong Kong patient, genomic sequencing determined that the patient’s first infection was caused by a virus from clade V, while the second was caused by a virus from clade G. This strongly suggests that the patient was infected on two separate occasions, in different parts of the world.

Is the occurrence of reinfection surprising? The possibility of reinfection with SARS-CoV-2 has been widely argued. Several lines of evidence have been used to contend against it. Until the announcement from Hong Kong, evidence in support of reinfection had not been published. On the other hand, the occurrence of SARS-CoV2 reinfection is not surprising, based on experience with other infectious diseases. “Sterilizing immunity,” or complete protection from infection after immunologic priming by natural infection or vaccination is often an elusive target, either because short-term immunity is not fool proof or because immunity tends to wane over time. Evidence from animal studies demonstrate the possibility of SARS-CoV-2 reinfection despite immunologic priming. If reinfection is possible, why are the first cases of this are only coming up being reported now? Will there be more cases in the future? It is possible there have been other cases of reinfection that have not been detected or convincingly investigated. In essence, public health surveillance systems are not set up to identify cases of reinfection.

Based on current information, it is difficult to predict how commonly reinfection will occur, but it is useful to explore whether features of the Hong Kong and Nevada cases make those patients’ situations more or less applicable to other patients. As for timing of reinfection, it is unclear how much the time period between infections, 4.5 months in the case of the Hong Kong patient, and six weeks in the case of the Nevada patient, may have contributed to the patients’ risks for reinfection. Studies have shown that SARS-CoV-2 antibodies can decline rapidly within a few weeks or months of infection but again, the role that antibodies play in immunologic protection is unclear. It is possible these patients were poorly protected against reinfection and were reinfected as soon as they were next exposed to SARS-CoV-2. Generally speaking, immunologic protection induced by natural infection or vaccination tends to wane over time. Hence the possibility that an effective COVID-19 vaccine may need to be administered repeatedly in order to maintain sufficient immunity. It is possible that as travel restrictions ease and population movement increases, exposure to SARS-CoV-2 clades that have not been previously encountered may increase the risk of reinfection. Concerns have also been expressed as to whether immune enhancement may occur for SARS-CoV-2, and in particular, if vaccination against COVID-19 could precipitate severe disease if post-vaccination infection occurs. At this time, there is no evidence from human or animal studies that SARSCoV-2 infection can precipitate immune enhancement of the disease.

Clearly a lot more scientific information is needed before tangible conclusions can be arrived at. Our perceptions on the capabilities of this blight will change over time when more and more details and research evidence is brought to light in the course of time. However, in view of the mayhem that has so far been wreaked by the virus, time is perhaps at a premium. As time is of the essence, the onus is on dedicated researchers world-wide to unravel some of these mysteries as soon as possible.

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Features

Strong on vocals

Published

3 days ago

2021/04/13

Sahan Weerasooriya

The group Mirage is very much alive, and kicking, as one would say!

Their lineup did undergo a few changes and now they have decided to present themselves as an all male group – operating without a female vocalist.

At the helm is Donald Pieries (drums and vocals), Trevin Joseph (percussion and vocals), Dilipa Deshan (bass and vocals), Toosha Rajarathna (keyboards and vocals), and Sudam Nanayakkara (lead guitar and vocals).

The plus factor, where the new lineup is concerned, is that all five members sing.

However, leader Donald did mention that if it’s a function, where a female vocalist is required, they would then feature a guest performer.

Mirage is a very experience outfit and they now do the Friday night scene at the Irish Pub, in Colombo, as well as private gigs.

Features

Dichotomy of an urban-suburban New Year

Published

3 days ago

2021/04/13

Sahan Weerasooriya

Ushered in by the ‘coo-ee’ of the Koel and the swaying of Erabadu bunches, the Sinhala and Tamil New Year will dawn in the wee hours of April 14. With houses to clean, preparation of sweetmeats and last-minute shopping, times are hectic…. and the streets congested.

It is believed that New Year traditions predated the advent of Buddhism in the 3rd century BC. But Buddhism resulted in a re-interpretation of the existing New Year activities in a Buddhist light. Hinduism has co-existed with Buddhism over millennia and no serious contradiction in New Year rituals are observed among Buddhists and Hindus.

The local New Year is a complex mix of Indigenous, Astrological, Hindu, and Buddhist traditions. Hindu literature provides the New Year with its mythological backdrop. The Prince of Peace called Indradeva is said to descend upon the earth to ensure peace and happiness, in a white carriage wearing on his head a white floral crown seven cubits high. He first plunges, into a sea of milk, breaking earth’s gravity.

The timing of the Sinhala New Year coincides with the New Year celebrations of many traditional calendars of South and Southeast Asia. Astrologically, the New Year begins when the sun moves from the House of Pisces (Meena Rashiya) to the House of Aries (Mesha Rashiya) in the celestial sphere.

The New Year marks the end of the harvest season and spring. Consequently, for farming communities, the traditional New Year doubles as a harvest as well. It also coincides with one of two instances when the sun is directly above Sri Lanka. The month of Bak, which coincides with April, according to the Gregorian calendar, represents prosperity. Astrologers decide the modern day rituals based on auspicious times, which coincides with the transit of the Sun between ‘House of Pisces’ and ‘House of Aries’.

Consequently, the ending of the old year, and the beginning of the new year occur several hours apart, during the time of transit. This period is considered Nonegathe, which roughly translates to ‘neutral period’ or a period in which there are no auspicious times. During the Nonegathe, traditionally, people are encouraged to engage themselves in meritorious and religious activities, refraining from material pursuits. This year the Nonegathe begin at 8.09 pm on Tuesday, April 13, and continues till 8.57 am on 14. New Year dawns at the halfway point of the transit, ushered in bythe sound of fire crackers, to the woe of many a dog and cat of the neighbourhood. Cracker related accidents are a common occurrence during new year celebrations. Environmental and safety concerns aside, lighting crackers remain an integral part of the celebrations throughout Sri Lanka.

This year the Sinhala and Tamil New Year dawns on Wednesday, April 14, at 2.33 am. But ‘spring cleaning’ starts days before the dawn of the new year. Before the new year the floor of houses are washed clean, polished, walls are lime-washed or painted, drapes are washed, dried and rehang. The well of the house is drained either manually or using an electric water pump and would not be used until such time the water is drawn for first transaction. Sweetmeats are prepared, often at homes, although commercialization of the new year has encouraged most urbanites to buy such food items. Shopping is a big part of the new year. Crowds throng to clothing retailers by the thousands. Relatives, specially the kids, are bought clothes as presents.

Bathing for the old year takes place before the dawn of the new year. This year this particular auspicious time falls on April 12, to bathe in the essence of wood apple leaves. Abiding by the relevant auspicious times the hearth and an oil lamp are lit and pot of milk is set to boil upon the hearth. Milk rice, the first meal of the year, is prepared separate. Entering into the first business transaction and partaking of the first meal are also observed according to the given auspicious times. This year, the auspicious time for preparing of meals, milk rice and sweets using mung beans, falls on Wednesday, April 14 at 6.17 am, and is to be carried out dressed in light green, while facing east. Commencement of work, transactions and consumption of the first meal falls on Wednesday, April 14 at 7.41 am, to be observed while wearing light green and facing east.

The first transaction was traditionally done with the well. The woman of the house would draw water from the well and in exchange drop a few pieces of charcoal, flowers, coins, salt and dried chillies into the well, in certain regions a handful of paddy or rice is also thrown in for good measure. But this ritual is also dying out as few urban homes have wells within their premises. This is not a mere ritual and was traditionally carried out with the purification properties of charcoal in mind. The first water is preferably collected into an airtight container, and kept till the dawn of the next new year. It is believed that if the water in the container does not go down it would be a prosperous year. The rituals vary slightly based on the region. However, the essence of the celebrations remains the same.

Anointing of oil is another major ritual of the New Year celebrations. It falls on Saturday, April 17 at 7.16 am, and is done wearing blue, facing south, with nuga leaves placed on the head and Karada leaves at the feet. Oil is to be applied mixed with extracts of Nuga leaves. The auspicious time for setting out for professional occupations falls on Monday, April 19 at 6.39 am, while dressed in white, by consuming a meal of milk rice mixed with ghee, while facing South.

Traditionally, women played Raban during this time, but such practices are slowly being weaned out by urbanization and commercialisation of the New Year. Neighbours are visited with platters of sweetmeats, bananas, Kevum (oil cake) and Kokis (a crispy sweetmeat) usually delivered by children. The dichotomy of the urban and village life is obvious here too, where in the suburbs and the village outdoor celebrations are preferred and the city opts for more private parties.

Features

New Year games: Integral part of New Year Celebrations

Published

3 days ago

2021/04/13

Sahan Weerasooriya

Food, games and rituals make a better part of New Year celebrations. One major perk of Avurudu is the festivals that are organised in each neighbourhood in its celebration. Observing all the rituals, like boiling milk, partaking of the first meal, anointing of oil, setting off to work, are, no doubt exciting, but much looked-forward-to is the local Avurudu Uthsawaya.

Avurudu Krida or New Year games are categorised as indoor and outdoor games. All indoor games are played on the floor and outdoor games played during the Avurudu Uthsava or New Year festival, with the whole neighbourhood taking part. Some of the indoor games are Pancha Dameema, Olinda Keliya and Cadju Dameema. Outdoor games include Kotta pora, Onchili pedeema, Raban geseema, Kana mutti bindeema, Placing the eye on the elephant, Coconut grating competition, Bun-eating competition, Lime-on-spoon race, Kamba adeema (Tug-o-War) and Lissana gaha nageema (climbing the greased pole). And what’s an Avurudhu Uthsava sans an Avurudu Kumari pageant, minus the usual drama that high profile beauty pageants of the day entail, of course.

A salient point of New Year games is that there are no age categories. Although there are games reserved for children such as blowing of balloons, races and soft drinks drinking contests, most other games are not age based.

Kotta pora aka pillow fights are not the kind the average teenagers fight out with their siblings, on plush beds. This is a serious game, wherein players have to balance themselves on a horizontal log in a seated position. With one hand tied behind their back and wielding the pillow with the other, players have to knock the opponent off balance. Whoever knocks the opponent off the log first, wins. The game is usually played over a muddy pit, so the loser goes home with a mud bath.

Climbing the greased pole is fun to watch, but cannot be fun to take part in. A flag is tied to the end of a timber pole-fixed to the ground and greased along the whole length. The objective of the players is to climb the pole, referred to as the ‘tree’, and bring down the flag. Retrieving the flag is never achieved on the first climb. It takes multiple climbers removing some of the grease at a time, so someone could finally retrieve the flag.

Who knew that scraping coconut could be made into an interesting game? During the Avurudu coconut scraping competition, women sit on coconut scraper stools and try to scrape a coconut as fast as possible. The one who finishes first wins. These maybe Avurudu games, but they are taken quite seriously. The grated coconut is inspected for clumps and those with ungrated clumps are disqualified.

Coconut palm weaving is another interesting contest that is exclusive to women. However men are by no means discouraged from entering such contests and, in fact, few men do. Participants are given equally measured coconut fronds and the one who finishes first wins.

Kana Mutti Bindima involves breaking one of many water filled clay pots hung overhead, using a long wooden beam. Placing the eye on the elephant is another game played while blindfolded. An elephant is drawn on a black or white board and the blindfolded person has to spot the eye of the elephant. Another competition involves feeding the partner yoghurt or curd while blindfolded.

The Banis-eating contest involves eating tea buns tied to a string. Contestants run to the buns with their hands tied behind their backs and have to eat buns hanging from a string, on their knees. The one who finishes his or her bun first, wins. Kamba adeema or Tug-o-War pits two teams against each other in a test of strength. Teams pull on opposite ends of a rope, with the goal being to bring the rope a certain distance in one direction against the force of the opposing team’s pull.

Participants of the lime-on-spoon race have to run a certain distance while balancing a lime on a spoon, with the handle in their mouths. The first person to cross the finish line without dropping the lime wins. The sack race and the three-legged race are equally fun to watch and to take part in. In the sack race, participants get into jute sacks and hop for the finish line. The first one over, wins. In the three-legged race one leg of each pair of participants are tied together and the duo must reach the finish line by synchronising their running, else they would trip over their own feet.

Pancha Dameema is an indoor game played in two groups, using five small shells, a coconut shell and a game board. Olinda is another indoor board game, normally played by two players. The board has nine holes, four beads each. The player who collects the most number of seeds win.