En av frågorna många har är varför regeringar och många internationella hälsovårdsmyndigheter väljer att införa reserestriktioner och stänger skolor, medan WHO inte rekommenderar detta just nu. jag ska försöka besvara detta. Det handlar om att vinna tid!
Om man läser WHO:s material ser man att WHO inte rekommenderar att man begränsar resandet eller stänger skolor. (källa) Ändå genomförs detta och de flesta politiker, myndigheter och experter är för det. Varför?
Jo det handlar om att vinna tid. Världen är oförberedd på en pandemi. Mycket mer oförberedd än vi kan ana. Dessutom har vi avvecklat beredskapslager och annat som fanns under kalla kriget med det glada tillropet ”aldrig mera krig eller kris eller naturkatastrof”. Vid det här laget är tanken alla politiker har ”VI MÅSTE VINNA TID”! Varje vecka man kan få är guld värd. Man tar några steg närmare ett flunsavaccin och man kan producera skyddsmaterial och utbilda personal och förbereda samhället.
WHO rekommenderar som sagt inte skolstängningar och reserestriktioner, men de medger att man kan vinna tid. Det är tabeller som denna (hämtad härifrån) som experter och politiker sitter och funderar över just nu.
Table 3. Simulated effects of the implementation of internal travel restrictions on the spread and duration of pandemic or epidemic influenza
Jag ska ta ett till exempel så ni förstår. Ytterligare en artikel hämtad från WHO. (källa här)
In Italy, relatively large delays were reported in reaching an influenza A(H5N1) peak – i.e. 7–37 days, depending on the level of influenza transmissibility and the extent of the restrictions simulated.17 Travel restrictions had no beneficial effect on attack rate if the level of strain transmissibility was moderate or high.17 In a more recent review, it was estimated that introduction of pandemic influenza into the United Kingdom could be delayed by up to 2 months if there was an almost complete – e.g. 99.9% – ban on air travel.20 However, the size of the effect was considerably reduced, to just 1–2 weeks, if the level of restriction was lowered to 90%.20
Similar observations were made in an assessment of the impact of restrictions of air, land and sea travel on the introduction of H1N1 pdm09 into Hong Kong Special Administrative Region (SAR), China.34 In this study, it was estimated that restrictions of 90% and 99% on all modes of transportation would delay the epidemic peak by up to 6 and 12 weeks, respectively, when R0 was set to 1.4.34 When R0 was set to 1.7, a restriction of 99% on all modes of transportation would delay the epidemic peak by up to 8 weeks and halve the cumulative attack rate. Air travel restrictions appeared to be the most effective isolated intervention, even though most infected cases would probably enter Hong Kong SAR by land travel from mainland China.34
Although one review of the evidence from mathematical modelling concluded that air travel bans would probably have a similar effect irrespective of the pandemic’s country of origin,21 another report believed that the effectiveness of such restrictions would vary according to the geographical source of the pandemic.31 If air travel bans delayed the epidemic so that it coincided with the usual influenza season, the apparent number of cases and the size of the peak in the epidemic could both increase.31 However, the opposite trends might be observed if the travel restrictions coincided with a period of low strain transmissibility.31
By restricting air travel by 95%, it should be possible to delay pandemic spread across the USA – of an infection originating in Sydney or Hong Kong SAR – by 2–3 weeks.31 However, there was no corresponding impact if the geographical origin of the pandemic was London because of London’s high flight densities and interconnectivity.31 The selective cancellation of a quarter of all connection flights between 500 major cities worldwide could be more effective than the closure of all of the cities’ airports – reducing the number of infected travellers by an additional 19%.32
A review of air travel restrictions between Asia and the United Kingdom indicated that such restrictions would stop no more than 90% of infected travellers from the pandemic’s country of origin.21 If air travel from all affected countries was restricted by 90.0% and 99.9%, the pandemic wave would be delayed by 3–4 weeks and up to 4 months, respectively,21,28 but such intensive restrictions would clearly have negative social and economic impacts. A systematic review found that extensive air travel restrictions – e.g. restrictions of more than 90% – could delay the spread of pandemics by up to 4 months if the strains involved had low to moderate transmissibility.7 However, such restrictions appeared ineffective if the strains involved had high transmissibility – i.e. if R0 was 2.4.7 In general, a combination of interventions appeared to be more effective than the implementation of travel restrictions in isolation.7
(…)Box 2. Summary of findings of the 23 studies assessed
Internal travel restrictions: general observations
- Have limited effectiveness
- Delay pandemic spread by about 1 week
- Delay pandemic peak by about 1.5 weeks
- Have little impact on magnitude of pandemics – e.g. they may reduce attack rates by <>
- Simulated impact is particularly weak in scenarios that involve strains with high transmissibility
Internal travel restrictions: risk of bias assessment
- Relevant studies have low to moderate risk of bias
- Paucity of data on terrestrial travel may have led to an overestimation of the impact of travel restrictions
- Many simulations take no account of the characteristics of human populations – e.g. the mixing and variation of susceptibility across age groups – or of seasonality. Such limitations could well have affected the simulated spread of pandemic waves and impacts of interventions
International travel restrictions: general observations
- Have limited effectiveness – e.g. 90% air travel restriction in all affected countries may delay spread of pandemics by 3–4 weeks
- Have minimal impact on the magnitude of pandemics, typically reducing attack rates by less than 0.02%
- May prolong the seasonal influenza season
- May result in higher epidemic peak if resultant delay causes pandemic wave to coincide with seasonal influenza wave
- Simulated impact particularly weak in scenarios that involve strains with high transmissibility
- Extensive restriction of international air travel might delay introduction of a pandemic into a country by up to 2 months and delay pandemic spread by 3–4 months
- Would not prevent introduction of a pandemic into any given country
- May give time for other interventions – e.g. the production and distribution of effective vaccines and antiviral drugs
- Social and economic impacts need to be evaluated
International travel restrictions: specific measures
- May have benefits compared with more widespread restrictions – e.g. in one simulation, compared with the closure of all of the cities’ airports, the targeted reduction of a quarter of flight connections between 500 major cities gave a greater reduction in the number of infected travellers
- Compared with banning air travel by adults, the banning of air travel by children may be more effective at delaying the spread of a pandemic but is socially impractical
International travel restrictions: risk of bias assessment
-
Relevant studies have low to moderate risk of bias
-
A paucity of data on travel by sea and land may have led to an overestimation of the impact of air travel restrictions on the containment of influenza pandemics
-
Much of the information available on air travel has a lack of detail on flight destinations and numbers of travellers and this may have led to inaccurate assumptions being made about the spread of influenza
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Again, many simulations take no account of the characteristics of human populations – e.g. the mixing and variation of susceptibility across age groups – or of seasonality and such limitations could well have affected the simulated spread of pandemic waves and impacts of interventions
-
When simulating novel pandemic strains, validation of models was an issue; mathematical models need to be validated against surveillance data to improve their value as predictive tools for policy-makers
Som ni kan se pratar vi totalt om många månader man kan vinna i tid genom radikala åtgärder.
Samma sak gäller för WHOs rekommendationer om masstest. Inget land, mer än Kina och Sydkorea, har just nu kapacitet att göra masstest i den skala WHO rekommenderar. Tyvärr. Så man får vinna tid tills man lyckats få fram de där miljonerna test som man behöver.
Detta är ingen enkel sak. Man måste behålla världsekonomin igång och tillåta folk att ta sig till jobben, där det är möjligt, samtidigt som man tar till så många begränsningar för folk som möjligt. Alla politiker och experter har vid detta läget bittert insett att idioter (ursäkta uttrycket) på 90talet avvecklade alla våra beredskapslager. Så världsekonomin måste hållas igång. Balansen mellan behovet att vinna tid och behovet att hålla ekonomin igång kommer att vara svår att bibehålla. Men det är där vi är, vare sig vi vill det eller inte.
Dilemmat med Sveriges strategi just nu är att vi riskerar att inte vinna de där veckorna och månaderna som alla andra länder försöker skaffa sig. Om det är rätt eller fel vet jag inte. Men i skrivande stund noterar jag att samtliga länder i världen som jag kollat på, utom Sverige, Vitryssland och Tonga, infört skolstängningar. Dessutom är Trump mot sådana åtgärder men det ska noteras att de flesta delstater i USA på eget bevåg infört de restriktionerna.)
Vad politikerna runt om i världen gör är faktiskt att de noga följer vad WHO och experterna säger. Och de ser att man kan vinna tid, och de agerar på det!
PS
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