Lecture 29: Covid-19

Question 1

what are the host factors for covid-19?

Answer 1

Risk factors for more severe outcome:

• non-immune - a population with low immunity increases chance of pandemic (with covid, no one had experience covid before so there was no immunity)
• age
• co-morbidities e.g. asthma, poor nutrition (things to lower immune system)

lower risk does not mean no risk

Question 2

what are the factors of the agent for covid?

Answer 2

• agent - SARS-CoV-2
• virus was new to humans
• coronavirus - other cause colds but also some severe acute respiratory syndromes (SARS,MERS). other version of coronavirus haven’t caused pandemics
• Person to person transmission (droplets, aerosols mostly)
• wide range of symptoms with different severity and length
• asymptomatic infectiousness

Question 3

what are environmental factors of covid?

Answer 3

• it depends on the way people mix e.g. travel and the frequency/mixing of contacts
• social and economic environment
• political context
• poor housing increases risk - overcrowding, poor ventilation

Question 4

what makes a pandemic?

Answer 4

• non-immune population
• transmissability
• route/time of transmission
• lack/failure of local control

Question 5

what is surveillance?

Answer 5

public health serveillance is the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for us in public health action to reduce morbidity and mortality and to improve health

image: serveillance model

Question 6

what is the IHR?

Answer 6

the international health regulations (IHR) strengthens health security by requiring countries to report to WHO if there is something to worry about

Question 7

what are the 3 types of data collection?

Answer 7

• passive
• active
• sentinel

Question 8

what is passive data collection?

Answer 8

• person making a diagnosis informes the surveillance system
  e. g. notifiable diseases (covid is on this list) and self-reporting positive covid test online

Question 9

what is active data collection?

Answer 9

• surveillance organisation seeks information from health care providers
• ministry contact DHBs and asks how many people have covid in the hospital today

Question 10

what is sentinel data collection?

Answer 10

• ‘sentinel health event’
• sentinel repoting usually GPs

e.g. influenza reports. GP practices tell how many influenze-like cases they see in that day/week

Question 11

what is the direct and indirect protection of immunisation?

Answer 11

Indirect - non-vaccinated population is protected by other people being vaccinated

Direct - difference of risk between a vaccinated and not vaccinated person

Question 12

what does this tell us about immunisty?

Answer 12

the large the R₀ is, the higher the need for vaccinated people

in other words, % of vaccinated people in order to achieve herd immunity

Question 13

how did the covid vaccination come about?

Answer 13

• genome of SARS-CoV-2 was sequenced by 10 Jan 2020
• manny vaccine candidates tested from early in the pandemic
• several different types of vaccine, using technologt developed over previous decades for other vaccines, went into clinical trials by mid 2020
• there were extensive trials during 2020
• regulatory processes for these vaccines were prioritised
• rollouts around the world started in early 2021