Dal
rischio contagio in volo alla quarantena!
International
Air Transport Association (IATAta) ha divulgato un Report di 13
pagine denominato ”Restarting
aviation following COVID-19 Medical evidence for various strategies
being discussed as at 07 July 2020 IATA Medical Advisory Group. E' un
testo base che delinea le procedure e le misure che le organizzazioni
internazionali ed ogni singolo Stato dovrebbero analizzare ed
attivare.
Restarting aviation following COVID-19
Medical evidence for various strategies being
discussed as at 07 July 2020
IATA Medical Advisory Group
Introduction Many international groups are exploring possible
pathways to facilitate a “restart” of international airline
aviation.
The resumption of international flights will require a number of
hurdles to be crossed in order for Governments to allow travel, and
further hurdles in terms of the passenger journey, which includes the
airports of departure and arrival, the flights themselves, and other
elements. Discussion by all of the groups involved includes a number
of key elements which depend on sound medical evidence. The aim of
this note is to review the current state of medical evidence
regarding those elements. The state of knowledge is changing rapidly;
hundreds of research articles have been published since the start of
the outbreak, and an enormous amount of work is in progress with both
researchers and industry. Therefore, this document must be read with
the latest review date in mind. There are many logistical, financial,
and political aspects to the restart plans well beyond the scope of
this discussion, which will be confined to the medical aspects. There
are also reports specific to airports and immigration processes which
are also out of scope here. The report has been prepared by IATA’s
Medical Advisor along with the Medical Advisory Group of 10 airline
medical directors, on the basis of extensive review of available
literature, advice and expertise during the pandemic thus far.
Re-start requires two key components: first, Governments must be
prepared to allow passengers to travel, between countries and
regions. Secondly, passengers must have sufficient confidence that
they can travel safely, and achieve what they wish to do on their
journey. For the passenger journey, an acceptable risk of inflight
transmission is a key factor, but this is along with other
considerations such as risk of illness while away, risk of being
quarantined, availability of safe and suitable accommodation,
availability of travel insurance, etc. For Governments, in-flight
transmission is secondary to the greater risk of importation of
people who are incubating the illness and can become sources of
infection. This is a more challenging problem to solve, but will
employ many of the same layers of protection which are discussed
here.
In-flight Transmission
Little is available in the way of published research on in-flight
transmission of COVID-19. One paper from Canada reports careful
follow up of a long-haul flight on which someone later confirmed to
have been unwell at the time, but no secondary cases resulted. A
recent public report shows that a flight on 31 March from USA to
China Taipei with 12 people subsequently confirmed to be symptomatic
at the time of flight, generated no secondary confirmed cases from
the 328 other passengers and crew members, who all tested negative. A
public health investigation into a flight from UK to Vietnam on 2
March 2020 suggests transmission by one passenger to up to fourteen
other passengers (twelve of whom were seated nearby the presumed
index case) and a cabin crew member. Initial information has been
obtained from this investigation but a formal study is expected in
due course. This is the only event known to IATA of suspected
on-board transmission to multiple people. By contrast, an informal
survey of 18 major airlines in correspondence with IATA has
identified, during Jan-Mar 2020, just four episodes of suspected
in-flight transmission, all from passenger to crew, and a further
four episodes of apparent transmission from pilot to pilot, which
could have been in-flight or before/after (including layover); there
were no instances of suspected passenger-to-passenger transmission
reported by the group of airlines. The group of airlines represents
14% of global traffic for that period. A request to a much larger
group of 70 airlines (representing half of global passenger traffic)
also failed to identify any cases of suspected passenger-to-passenger
transmission. And finally, closer analysis with IATA was able to be
carried out by four airlines which had close contact with local
public health authorities during the outbreak. The four airlines
(with a combined annual traffic of 329 billion RPK) together followed
up around 1100 passengers who were identified as confirmed cases
having recently flown. The flights in question represent about 125000
passengers. There was one possible secondary passenger case
identified in the total, along with just two crew cases, thought to
be the result of possible in-flight transmission. By comparison, a
recent article from Shenzhen China on transmission quotes an overall
transmission rate of 6.6% across modes of contacts (household,
travel, or meals), which would equate to a predicted 72 cases from
those 1100 passengers, compared with the three that we have observed.
The reasons for the apparently low rate of in-flight transmission are
not known but could encompass a combination of the lack of
face-to-face contact, and the physical barriers provided by seat
backs, along with the characteristics of cabin air flow. Further
study is under way.
Multi-layered approach:
In the absence of a single measure which can achieve high-levels
of risk reduction, the alternative is to use a combination of
approaches to mitigate the risk as far as practical. This is
essentially the approach being applied at present for those services
that continue to operate for cargo and repatriation flights. The
combination of intrusive and burdensome measures creates a travel
experience far removed from ‘normal’ operations and one which is
unlikely to be commercially sustainable for any significant period.
However this provides a potential pathway towards recovery and
reconnection. It is likely that there will be a stratified approach
which employs more measures to routes, or passenger groups, which
entail higher risk at the time. Summary: A multi-layered approach
will almost certainly be required in the initial stages.
Temperature screening
Fever (elevated core body temperature) is an early sign of
COVID-19 in some people, but by no means all. Surface temperature
measurement is less reliable than core temperature, but is easier,
which is why temperature screening usually involves a measurement of
surface temperature. The various methods include handheld measuring
devices which may be contact (eg aural) or contactless, remote
thermal scanning, and newly developed devices with cameras which are
apparently able to measure temperate, pulse and respiration rate from
a distance. All these methods have deficiencies. Temperature
screening has been employed at both departure and arrival. It will
miss many of those with early illness, asymptomatic illness, those
whose symptoms do not include fever, and in some cases, those who
have taken antipyretic medication (such as acetaminophen/paracetamol)
to lower their temperature. It has been documented however, that in
the early stages of the COVID-19 pandemic, several new cases were
detected in passengers who underwent routine temperature checks after
arriving at their destination. Survey research during the COVID-19
outbreak has indicated that airline passengers are reassured by
temperature screening undertaken in airports. It could also have an
effect of deterring passengers who might otherwise travel when
feeling unwell. Temperature screening needs to be done with validated
equipment, and if done manually, by staff who have appropriate
training and personal protective equipment (PPE). IATA maintains that
it should not be the role of airline staff to carry out such
screening. Even under these conditions there will be false positive
and false negative results. Temperature (and other) screening is more
likely to be useful in populations where COVID-19 prevalence is
higher (such as returned travelers) than in low-prevalence groups
such as the general travel population. Summary: Temperature screening
has deficiencies and should be undertaken with appropriate
precautions. It may be of some benefit, applied selectively along
with other measures.
Symptom screening
Many countries have been using a questionnaire to ask travelers
about symptoms (usually fever, cough, breathing difficulties) as an
added screen to detect people possibly currently suffering from
COVID-19, usually upon arrival; a declaration of symptoms could also
be added to a nation’s electronic visa process as another layer of
protection prior to travel. Obviously it depends on the honesty of
the answers, but being required to make a declaration of being
symptom-free could provide a deterrent to travelling while unwell.
Various groups are developing electronic applications which can
assist with screening for symptoms, often in conjunction with
applications to facilitate contact tracing. It is noted that many
countries already had symptom screening in place when the virus was
imported; many studies have now documented the level of asymptomatic
spread, which contributes to transmission and limits the usefulness
of symptom screening. Summary: Symptom screening is a useful adjunct
to other measures but has significant limitations.
Use of masks and PPE
The primary method of spread of COVID-19 is exhaled droplets, with
a secondary method of spread from those droplets via surfaces and
hands. There is ongoing debate as to the level to which smaller
aerosol particles, which can remain suspended for longer times or
distances, contribute to spread. IATA’s earlier guidance has
reflected WHO advice that the use of surgical masks should be
reserved for those who are unwell or those who are caring for those
who are unwell. As a protection for individuals in public places,
without close contact with others, it is of very limited benefit;
however, increasingly, authorities have been promoting or requiring
the use of non-medical face coverings for those who are in public,
especially in situations where physical distancing is not possible.
This “source control” strategy is intended to protect the public
from the wearer, rather than to protect the individual – by
creating a physical barrier to the exhalation of droplets. Studies
increasingly suggest that such use of face coverings is effective at
reducing droplet spread, and this is of potential benefit where
physical distancing cannot be achieved; WHO has recently incorporated
this strategy in its advice, and provided information on how to
create suitable masks from material, to avoid depleting supplies of
medical grade disposable masks which are required for use by health
care workers. As the pandemic has progressed, more aviation
authorities have encouraged or required passengers to wear face
coverings. Similarly for crew members, it is expected that the use of
surgical masks and gloves, with appropriate instruction and training,
and disposal methods, and associated with meticulous hygiene, will
provide protection, as well reassurance for both them and their
passengers. It is reasonable to require mask use for those airline
workers in situations where physical distancing cannot be ensured
(not just crew but also gate staff, ground staff who board the
aircraft, etc), until risk is judged to be sufficiently reduced. Many
countries have gone further and required full PPE for cabin crew.
This is not an infallible protection but forms one element of an
overall set of measures. Summary: Face coverings for passengers along
with suitable PPE for crew and other airline staff are a useful
element of a multi-layered protection strategy.
Physical distancing
The mainstay of interrupting the spread of COVID-19 is preventing
people from having close contact with each other, since the most
efficient method of spread is by inhalation of exhaled droplets from
an infected person. This is presumed to be most efficient when
coughing, sneezing or talking, face to face. All of the measures
employed currently around the world to slow the spread make use of
maintaining distance between individuals as much as possible, and
guidance around the ideal distance ranges from 1-2 metres (3-6 feet).
It is possible to modify airport check-in, immigration, security,
departure lounge, and boarding processes in such a way as to ensure
such physical distancing, and the Airports Council International
(ACI) has published guidance on this. On board the aircraft, it is
difficult to achieve such a high degree of distancing, unless the
aircraft loadings are so light as to be uneconomical. However, other
protections are in place including the fact that people all face the
same direction rather than face-to-face, they generally remain in
their seat after boarding, except to visit bathrooms. Additional
possible protection is derived from the physical barrier of the seat
backs, and the direction of cabin air flow which is generally from
ceiling to floor, at a much higher rate than in public buildings,
with little lateral flow. Contamination of the supplied air is
reliably avoided by the presence of HEPA filters, which are installed
in those modern jet airliners which use recirculation. The greatest
challenges for distancing may relate to when passengers are moving,
particularly boarding, disembarking, and using bathrooms. Physical
distancing measures currently in use by airlines include: management
of the boarding process to minimize passengers passing each other;
limiting carry-on baggage; sequenced boarding rear first, window
first; allocation of bathrooms for each area; allowing only one
passenger at a time visiting the bathroom. Interactions of crew and
passengers face-to-face are avoided by pre-placing service items
(food, water, and trash containers) on seats before boarding.
Finally, these measures may be supplemented by the wearing of face
covers or masks by passengers and crew alike. Some airlines are
currently, while load factors are low, also achieving a degree of
distancing by leaving every second seat empty, or similar. In a
restart scenario this would be economically unviable. Given the data
presented above regarding in-flight transmission from passenger to
passenger, its justification would be questionable. There may however
be benefit in leaving empty seats in the region where crew are seated
(in their jump seats) face to face with passengers. Where possible,
leaving empty seats may further reduce risk although further study is
required regarding the nature and risk of droplet spread in the cabin
air environment. Study is currently under way employing review of
previous research, new computational modelling, and planning for
simulation studies. Summary: Physical distancing on board can be
achieved to a large degree especially during the airport processes
and boarding, but leaving large numbers of empty seats on a routine
basis is probably unsustainable.
Cleaning and Disinfection
While the primary route of transmission is direct respiratory
droplet spread (exhaled and then inhaled), fomite transfer via
surfaces and hands is also important, and in addition to the primary
preventive tool of hand hygiene, cleaning and disinfection of
frequently/recently touched surfaces is advised by WHO and other
health agencies. Concern has been heightened by research indicating
potential virus survival on a range of surfaces for a few days.
Cleaning with normal agents such as alcohol 60% is very effective at
destroying the virus on such surfaces, and other agents such as
quarternary ammonium compounds, commonly used in aviation, are also
effective; manufacturers have updated advice on compounds to be used.
On the aircraft, there is potential for transmission in this manner
particularly on short-haul flying where rapid turnarounds have
previously prevented extensive cleaning between sectors. Many
airlines have increased the frequency and extent of their routine
cleaning. Some regulators (including China CAAC and EASA) have
recommended particular cleaning procedures as a routine. It is likely
that improved routine cleaning provides reassurance to passengers,
whether or not it reduces risk of transmission. Another possibility
which has been adopted for rapid turnaround flights is for passengers
to be given material (alcohol wipes etc) to use on the surfaces in
their seat area, so that they know it has been done and have some
agency in the process; this has been shown to be reassuring for
passengers. There are other potential methods of disinfection such as
UV light and gaseous ozone which have not been evaluated in the
airline setting. Summary: Cleaning and disinfection procedures, in
excess of the previous norms, are part of the range of measures
required in a restart process.
COVID-19 Testing
Background: The mainstay of testing for current infection
(presence of virus) in the community is a polymerase chain reaction
(PCR) test which involves taking a swab of the upper throat and
amplifying the genetic material in a laboratory until it can be
detected and confirmed. An increasing number of regions (examples
include South Korea, Hong Kong SAR, Macao SAR, Austria, Luxembourg,
Iceland and China in conjunction with Singapore) have introduced
testing into their State requirements for travelers, either before
departure (perhaps incorporated into an electronic visa process), or
after arrival. All medical testing has limitations; even PCR can miss
some people with the infection, early in the illness, particularly if
the person has recently been infected and is still incubating; this
opens a window during which the person may become infected (and turn
positive), AFTER testing. Pre-departure testing means this window
occurs in the departure location. Post-arrival testing means that the
delay occurs in the arrival country and the person could infect
others while the result is awaited, unless isolated. For our specific
purposes of ensuring safe travel, the ideal time to test is
immediately prior to travel, and for convenience and simplicity, this
would be best done at the airport of departure. Another limitation,
even of PCR, is the converse problem: late in the illness it appears
that people can test positive without actually being infectious, so
this represents a false positive which is problematic for travelers,
whether it occurs in their own country or a foreign country for them.
Testing with throat swabs is also somewhat invasive and
uncomfortable, and requires the sample to be taken by a trained
person (usually a health care worker) who is also equipped and
competent with PPE. A technology which could be performed with saliva
would therefore provide a significant advantage, being able to be
performed more easily and more acceptably. Next, there is the
question of speed: this is improving, but with PCR tests there is a
delay waiting for the result – which is at best a few hours
currently. New testing: Many alternative technologies are now either
in development or available, which can either rapidly amplify the
genetic material, or can use other components of the virus (antigens)
such as surface proteins. In order to be able to be used as part of
the airport process (either departure or arrival) they would need to
be able to perform at speed (results well inside an hour) but also at
sufficient scale (hundreds of tests per hour) for this to be
practical. Ideal would once again be the use of saliva. Finally and
crucially, in order to be usable, the tests would be required to have
demonstrated extremely high reliability when compared with standard
PCR technology: firstly, they would require a very low false negative
rate (ideally less than 1%), but for the aviation setting probably
even more important is a very low false positive rate, because any
significant percentage of false positives will result in large
numbers of passengers having to cancel their travel when already at
the airport. This reliability needs to be certified by reputable
national or international authorities, whether scientific,
therapeutic, or public health . Summary: Rapid point-of-care testing
is an important potential extra layer of protection. Technology for
rapid on-site PCR tests, molecular tests and alternative antigen
tests, is advancing rapidly, and if validated by a reputable
scientific organization could be an additional layer of protection.
Suggested requirements are that this testing be:
- validated by a reputable National scientific, therapeutic, or
public health agency, to achieve less than 1% false negatives and
the lowest possible false positive rate compared with PCR;
- deployable in an airport setting, preferably using saliva and
able to be sampled without use of PPE;
- capable of scaling to achieve hundreds of tests per hour, with
results well inside one hour.
Antibody Testing There are many epidemiological estimates that the number of mild
recovered cases could greatly exceed the number of confirmed cases,
and with suitable widespread serology (antibody) testing, there may
be a large enough population of recovered and immune individuals.
Indeed, many serology studies of closed communities (small towns,
ships, etc) have shown a high proportion of individuals to have been
infected – however, in larger population studies the highest
proportions have been around 17% which is insufficient to provide a
significant population of immune individuals. It remains unclear for
how long immunity is maintained or its extent; some coronaviruses
generate relatively short-lived immunity and therefore this is not
yet a reliable protection. If antibody testing were adopted for use
in connection with an “immunity passport” (below), the testing
would initially need to have a short “validity” since the
duration of immunity would not be known. Furthermore, WHO advice has
consistently been that there are no validated and reliable antibody
tests available for use on an individual level, and that such tests
should be used only for studying populations to understand the
nature of the pandemic and its transmission. Summary: This is not
yet a reliable tool other than for epidemiological study. It has
potential when validated and supported by major health bodies such
as WHO, and with further experience.
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Immunity
Passports
This concept arises from the fact that once someone has recovered
from a viral infection they normally retain immunity; there is some
evidence from animal and human studies to suggest that immunity to
COVID-19 will be retained at least for some months. The concept of
immunity passports is that if someone can be documented as having
recovered from COVID-19 they are presumed to be immune, therefore
many of the normal protections would not be required; this would
mean that by showing their documentation (or incorporating it into a
prior electronic visa process), they could achieve the airport,
boarding and on-board processes bypassing many of the protective
steps such as face cover, temperature checks etc. Those airport
staff and aircrew who were immune could similarly omit many of the
requirements, including for PPE and physical distancing. The main
difficulty is that even now, the proportion of the population who
are recovered cases is very small – serological surveys have
typically shown less than 10% of the population with evidence of
immunity, although more recently London UK has shown around 17.5%.
These levels would not be enough to allow a significant restart, but
they are increasing over time. Furthermore, a proportion of those
cases have been diagnosed clinically rather than with laboratory
confirmation, and Governments are likely to require laboratory
documentation before granting such a passport, which would make the
population even smaller. However, as the pandemic progresses, it is
possible that the population of immune people may eventually become
big enough to make this a viable proposition. There are also
important potential unintended consequences of such a measure. For
example, granting of privileges to those who have recovered could
incentivize people to contract the disease. This “perverse
incentive” could tempt people to deliberately expose themselves,
and thereby undermine public health measures and propagate the
pandemic. Summary: Limited potential unless global spread continues
to a large proportion of the population. Some risks as ongoing
immunity is not assured; unwise at the current time.
Quarantine
One of the key measures which is being imposed by governments is
a period of quarantine for incoming travelers – almost universally
14 days, to exceed the 12 days which is considered the maximum
incubation period. There are considerable logistical difficulties
involved in this process to ensure that while all needs of
transport, accommodation, food, exercise, and communication are met,
there is no cross-contamination between those in quarantine. In many
cases, the quarantine is accompanied by COVID-19 testing so that the
measure is not solely dependent on people recognizing and reporting
symptoms. While this can be an effective means of ensuring any
imported cases do not spread, it is a major disincentive to travel,
particularly if required after both (outbound and return) legs of an
international journey. In situations where travel is between two
countries with similar levels of community transmission in the
community, any travelers who had been COVID-19 tested negative upon
departure, would be of lower risk than the non-tested members of the
surrounding community, so the argument could be advanced that they
should be subject to no more restrictions than the others in the
community. This may well even be the case when travel is from a
community with higher transmission risk than the destination;
testing procedures could therefore be one of the considerations
against which to balance a decision about quarantine. This goes
alongside the other measures in place such as: discouraging
symptomatic passengers from travelling; health declarations
including symptom screening; the measures adopted during travel as
outlined in the ICAO “Take-off” recommendations; and contact
tracing measures after arrival. By contrast, if traveling from an
area of low risk to one of high risk, then it is difficult to
support an argument for quarantine on arrival. These are all
questions for the government of the destination country to resolve.
Summary: Quarantine is a major inhibitor of travel and on a careful
analysis of the risks, governments may determine that it is not
justified in many scenarios.
Measures to assist contact tracing
Although the prime objective will be to prevent anyone travelling
while unwell, an important back-up to this is the ability to rapidly
identify and trace the contacts of anyone who, after travelling, is
discovered to have been infected at the time of travel. Measures to
assist and facilitate such tracing have been employed as part of
arrival procedures in some countries. They could be as simple as
providing contact details for follow-up if required. In many cases
these have made use of technology such as phone applications which,
with the user’s consent, allow their movements and even their
close contacts to be traced and tracked. The use of such
technologies could be a condition applied by governments to allowing
international (or indeed domestic) travel in a restart. A further
element to this would be ensuring early reporting of any instances
where passengers are unwell in flight, with symptoms consistent with
COVID-19. Ground-based medical services could have a role here in
ensuring public health processes are triggered. Summary: Procedures,
and technologies, for contact tracing are likely to be part of the
suite of required measures.
Measures related to crew members
In the current operations, aircrew (pilots and flight attendants)
are almost the only people travelling between countries. On
long-haul sectors, it is necessary for them to layover at
destination. Health authorities are allowing this to occur
contingent on strict procedures to prevent them becoming infected
while on layover. These have included social distancing (such as
being confined to a hotel room during layover, with meals
delivered), use of masks, special arrangements for transport, and
temperature checks. In a restart scenario, some crew protective
procedures are also likely to be one of the conditions for
governments allowing airline travel to increase. Indeed it is
strongly recommended that governments work with airlines in
determining what protections are appropriate. There are also a range
of in-flight procedures related specifically to crew aimed at
preventing transmission between passengers, or between crew and
passengers, and a separate IATA document details these. Summary:
procedures for crew in flight and during layover are likely to be a
significant part of the required measures to allow restart.
Treatment
If a medical treatment became available which drastically and
reliably reduced the mortality and severity of disease, then the
concerns of both Governments and travelers would be massively
reduced, potentially allowing a resumption of travel. No such
measures are currently available. Summary: Potentially a major help
but not yet available.
Vaccination
The eventual arrival of a reliable vaccine, with production
scaled up to allow widespread availability, would achieve immunity
for those vaccinated. However, best-case estimates of the time
course for reaching this situation are mostly not before the 2021
calendar year. It is not a certainty that a successful vaccine will
be produced, but there are large numbers under development and even
human testing. This would be the world’s first vaccine against a
coronavirus. If successfully produced and widely distributed, a
certificate of immunity such as mentioned above would become a
viable tool to facilitate travel. Summary: The best solution, being
vigorously pursued, but not yet in sight. This multi-layered
approach, incorporating many of the above possible protective
measures, is proposed as a pathway for aviation recovery